The third season of Only Murders In The Building, which comes to an end with today’s finale, has elevated Hulu’s murder mystery comedy to new heights. There’s a mystery filled with endless twists and turns, dozens of musical theatre Easter eggs, and a look that remains as timeless and distinctive as ever.

This season, Oliver Putnam (Martin Short) has returned to his Broadway roots to direct Death Rattle, a bizarre murder mystery play (the main suspect is a baby, which should give you a good idea of just how wild the plot seems to be). When Oliver’s star, Hollywood-transplant Ben Glenroy (Paul Rudd) dies on opening night, Arconia’s crime-podcasting trio begin their investigations.

But things are decidedly different for the group this season. Oliver is distracted by his play – after Ben’s death, he has the ludicrous idea to turn the baby into triplets and turn the play into a musical. He’s also got a (very touching) romance brewing with Loretta Durkin (Meryl Streep), an ageing actor who never quite landed her big break. Charles-Haden Savage (Steve Martin), meanwhile, is occupied with his own problems – his romance with Joy (Andrea Martin) is falling apart at the seams, while his anxiety about performing the show’s fast-paced patter song sends him spiralling into an imagined ‘white room’. Only Mabel Mora (Selena Gomez) is giving her full attention to the case. And she’s desperate to succeed – after all, she’s on the cusp of 30, and what does she have to show for it?

For Dana Covarrubias, who has designed costumes for all three seasons of the show, the latest season has offered an opportunity to explore new territory with the central trio, and, indeed, with the look of the entire show. The show’s film noir feel is amped up thanks to the addition of a theatrical production set in the 40s, while Mabel’s look has been given a mature upgrade, with the help of numerous Broadway influences that Covarrubias has peppered delicately into her designs. 

After season two saw Mabel dipping her toes into the art world, thanks largely to the influence of Cara Delevingne’s Alice, she is more focused than ever on the podcast.

“In season one, we really stuck to her sort of hero colour palette, which is a lot of marigolds and reds and warm oranges,” Covarrubias tells me. “In season two, we were really playing with Mabel exploring her artistic side – we kind of bumped everything up as far in terms of the colour palette – we gave her almost a watercolour palette. Very artistic.” 

In season three, Mabel has homed in on the podcast. For Covarrubias, it was the perfect opportunity to experiment with a new, stronger look.

“We really wanted to focus her wardrobe on reflecting that she’s the lead detective,” she says. “So, we were looking at more men’s tailoring and trench coats – stuff that just felt a little more detective-y, less artsy.”

But, stylistically, she remains distinctly Mabel Mora, mixing the “grungy, punky” look of season 1, with this “tailored look”.

As for Gomez, she was, as ever, fully on board with Mabel’s stylistic journey. “We’ve had such a great working relationship,” Covarrubias says. After three seasons, she knows exactly who Mabel is. “I would say the main conversation we have in a fitting is asking, ‘Does this feel like Mabel, or is it not quite her?’ She’s just very open and lets me and my team really take charge of the design of Mabel, which is amazing.”

And, of course, Mabel would not be Mabel without her jumpers. Howard (Michael Cyril Creighton) puts it best: Mabel is an “ace investigator with a closet full of cashmere – I want to be her in the next life.” And now, she’s got a collection of tailored wool coats that are also to die for.

I, like Howard, am also obsessed. So, I have to ask: where can I find Mabel’s clothes?

It’s a combination of vintage and clothes from physical shops in New York City and clothes sourced online, she tells me. Covarrubias has a team of shoppers combing through Bloomingdale’s, Macy’s, Saks and Nordstroms, as well as the “the smaller designer stores” in Soho. Online, Covarrubias and her team pour through The RealReal, The Outnet and Net-a-Porter.

“It’s really just a hunt,” she says after rattling through the lengthy list. “What’s great is that her style is so clear now it’s very easy for me. You’re just like, ‘Oh, that’s Mabel.’ It’s very clear what her pieces are.”

And underneath all of this, there is yet another aesthetic layer at work. Last season, Mabel’s looks borrowed from leading ladies of the 1940s in what she describes as a “Hitchcock theme”. Each of Mabel’s outfits this season, Covarrubias says, pays homage to a different Broadway musical.

“My general theme was Broadway and musicals,” she says. “We kind of reverse engineered a lot of Mabel’s looks where we were like, ‘OK, this episode her look should be inspired by Chicago.’”

She adds, “I think on my Instagram at some point I’ll go through and tell everyone my inspiration for each one. It’s been fun for me and my hope is that the fans will watch the season and try to figure it out.” 

While Gomez’s costumes may be inspired by the femme fatales of the 40s with a Broadway twist, Streep’s costumes are inspired by Streep herself. As Loretta, Covarrubias explains, Streep is playing what the team decided would be a sort of sliding doors version of herself. What if Streep hadn’t found success in New York in the 70s? Who would she be today? Where would she be? And what would she be wearing?

Covarrubias’s first port of call was to look at what Streep “was wearing back then”.

“[She wore] a very autumnal palette,” she says. “It has this interesting mix of very, very rich teals and these almost burnt crimsony deep, deep reds. That’s kind of what we were going for.”

Her look was classic, tailored and simple – surprisingly, a seamless fit with the 40s-inspired silhouettes and colour schemes already synonymous with the show.

The classic look is one that has also returned to style now. “It’s actually pretty in right now – this silhouette. The midi skirt that’s hitting the mid-calf with a high boot and a broad, sharp men’s blazer with a loose buttoned-down shirt under it. That’s kind of what she was wearing back then.” 

Loretta’s love affair with the theatre is also reflected in her wardrobe. After a lifetime dedicated to acting, Loretta dresses like a true shapeshifter – she is ready, at the drop of a hat, to transform into someone else.

“Meryl and I had a really great conversation about how she would dress and we came up with this concept that she’s either always trying to disappear – to be a wallflower – or she’s wearing something very characterful that maybe she stole from a production she was in. Something that feels very like Chekhovian or Shakespearean,” she says. “I thought it was an interesting concept.”

Shawls became Loretta’s transformational tools – she wears one in almost every scene she’s in.

“You know, she could wrap it around her shoulders and it’s a cape or she can tie it around her waist and it’s a skirt. It could become a toga!” she says. 

Loretta’s scarves also hinted visually at the sense of destiny woven into her budding relationship with Oliver.

“We liked how it also mirrored Oliver’s scarves,” she says. “They both just love scarves and that brought them closer together.”

Luckily, Streep loved the whole concept. 

“We had our first meeting on Zoom with our showrunner John Hoffman and I showed her some of my initial mood boards and she was very happy with them,” she recalls.

From that first meeting, Streep was deeply involved in bringing Loretta to life. “She was very interactive. She’s [one of those] people that really loves doing it [together],” she says.

In the first fitting, Covarrubias took Streep through the outfits she had picked out.

“It was just wonderful. She was honestly just so wonderful and so sweet,” she says. “It’s a moment I’ll never forget my entire life – she looked at me, grabbed me by both of my shoulders and she told me to my face that I’m a genius. I was just in a state of shock during that entire fitting that I was even getting to fit Miss Meryl Streep, the icon, but that’ll go down as one of the best moments of my life.”

Another key aspect of this season was designing the look of the Death Rattle play and later the musical version, Death Rattle Dazzle.

We see flashes of the show’s costumes throughout the season, and, by the finale, we’ve even seen the infamous breeding crabmen. 

“It was a fun, weird process, designing for a play that’s not really written,” she says. “We had a little bit of a breakdown of what the play was.” After all, they had already filmed one shot of the play at the end of season two, when Ben’s death on stage was teased. 

“We just knew that they were supposed to be in detective-esque looks. It was maybe 1940s – which is hard for costumes. But a few weeks in, we had a little bit of an outline of what the play was.”

The 40s look remained – a perfect fit for the timeless feel of the show and the grown-up new silhouettes worn by Mabel. Even Loretta’s classic look blended with the 40s costumes on stage. “That was good that [it all] kind of mirrored each other a little bit for us,” she says.

And then, there were the crabmen – the crazed-yet-genius brainchild of Oliver Putman.

“The crabmen were really funny,” she says. “It’s scripted, in the dialogue over and over and over. They’re all talking about these crabman, but we didn’t know what exactly they were. We were like, ‘What does that even mean?’” Throughout season three, Covarrubias played around with different crabmen concepts, until Hoffman found the crabmen look he had envisioned. 

A little like Meryl’s Chehovian scarves and Mabel’s patchwork jumpers, no one could have imagined that Oliver’s crabmen would work, but work they do. In a show that seamlessly blends the absurd and the heartfelt, it’s fitting that Covarrubias’s costumes are both stylistically classic and endlessly inventive – and, much like the show’s perpetual fanboy Howard, I consistently want all of them.

Season three of Only Murders In The Building is now available on Disney+.

Images: Patrick Harbron; Hulu