It is no overstatement to say that Judi Dench is one of the most formidable acting talents of her time – 55 industry awards, an illustrious stage career and a Best Supporting Actress Oscar for an eight-minute turn in Shakespeare In Love attest to that. You could be forgiven, then, for assuming the word starstruck is not one that enters into her vocabulary. But within a few minutes of meeting the icon, who turned 80 last December, it’s clear she’s as easily flustered as the rest of us.

“I had to go to the Oscars a while ago and Jack Nicholson walked past me. I couldn’t believe it,” she says wide-eyed. “You know how, in your mind, these famous actors are always huge – they’re vast – well he wasn’t actually that tall. But I was still completely bowled over. I got a bit silly; like a teenager. I had just presented an award and he walked past and said, ‘Good job, Jude.’ I pretended to be all suave and worldly but actually I was like a jelly inside.”

While Jack Nicholson might be the only person on the planet able to call Dame Judi Dench ‘Jude’ and get away with it; we’re far more eager to impress. There’s something regal about Judi – probably down to the elegant white hair and crisp English accent – I had to fight the urge to put on a churchly Sunday frock to meet her.

The heavyweight CV adds to her stateliness too. Her career, spanning six decades, is so multifarious she has cultivated an ability to take on an almost impossible range of characters. Whether it’s stony and cutting as M, head of MI6, in Bond; cantankerous and tart as Queen Elizabeth I in Shakespeare In Love; or endearingly naive as an Irish mother searching for her long-lost child in Philomena, she unfailingly and wholly inhabits a role, leaving you certain no-one else would have even touched the sides. Good going for someone once told by a producer she could never make it in films because her face “isn’t properly arranged”.

Self-deprecating, engaged and funny, she’s also a captivating conversationalist with a wonderfully maternal air. She’s also a well-known practical joker. She once got one over on Hollywood director Harvey Weinstein by telling him she’d got his name tattooed on her bum, then got her make-up artist to write his name on her behind, and showed him during lunch at The Four Seasons in New York.

We meet in Claridge’s where Judi is promoting The Second Best Exotic Marigold Hotel, which sees her reunite with Bill Nighy, Celia Imrie and Maggie Smith for a second hotel opening in vibrant Rajasthan. I catch her staring intently at a glass of orange juice on the table in front of her. “I’ve got that starey thing,” she warns me, chuckling but not moving her gaze from the glass. “I can’t look away.”

So with a charmingly non-Hollywood approach but a body of work behind her to rival any A-lister, who better to give us a little bit of guidance? With pen in hand and wearing my very best outfit, we asked the grand dame what advice she’d give her 30-year-old self…

Use fear to your advantage “Lots and lots of things scare me; but you just get on with it. Fright can transform into petrol. I get stage fright all the time; the more I act, the more I feel it. But you just have to use it to your advantage. Just like grief [Dench’s husband, actor Michael Williams died in 2001 from lung cancer], fear engenders a huge amount of energy and you have to make it work for the better, otherwise you’d crumble.”

Forge your own fashion path “Don’t wear things that people tell you you look good in. You almost always won’t look good in it. Often I see people and I think, ‘Does that person really like what they’re wearing or are they doing it to keep up with fashion?’ I have never worn anything fashionable for the whole of my life. I just wear old things which I like very much and have far too many of. Wear what you feel good in; it will look much chicer than wearing something fashionable that makes you feel ill-at-ease.”

Create your own opportunities “I don't think we need to make bucket lists, but we should be open to new opportunities. If opportunities don't come up – make them come up. I've seen a lot and travelled to a lot of places but I've never been to the Dulwich Picture Gallery in south London. I desperately want to go. They've got loads of Old Masters there and I've just heard they're getting a fake painting made by an artists' workshop in China and you have to go and guess which one it is. Well, I can't wait. I'm going to take my grandson, Sammy [17].”

Don’t be afraid to subvert the norm “I've disobeyed the rules ever since my very first acting role. It's seared into my memory. I was five and I played a snail. I was in brown tights and a romper suit and my father made me a huge shell. When it came to show night, my parents were in the audience. I was supposed to be crawling on my hands and knees but as soon as I spotted them I suddenly stood bolt upright to wave. My teacher, Mrs Meeby, shouted from the side of the stage, ‘Judith! Get down!'”

Keep learning “I'm a great advocate for not sitting back. I never think, ‘Oh my eyesight's bad, I can't possibly do this' [Dench suffers from macular degeneration]. I just want to learn new things all the time. I like to play a lot of games; Bananagrams, Categories and I do that thing where you open the dictionary every morning and learn five new words. Iíve just started to learn how to carve objects out of soapstone – birds and things. I'm absolutely hopeless at cooking, too so I'm considering taking some kind of course. I think it's very important to keep learning.”

Never fall out of love with life “Nothing is good about ageing. Nothing. Everyone looks at you and thinks, ‘Oh hello, so  you're about to drop off the bough….' But I hate the thought of [death]. People say to me, ‘Oh but think of the great wealth of things you've learnt'. Actually, I'd rather be younger and dumber. What a great thing to have a whole life ahead of you. When you're young, you stand up and get a funny twinge in your back and think nothing of it. If you're my age, you're going to have that for the rest of your life. But I refuse to be beaten by age. I'm in love with life. I won't give in.”

Always strive to be better “People call me a workaholic but I just love working. I feel very lucky to be part of the 2% of people who wanted to do something and were able to make a living at it. It might have been different if I'd turned out to be a bin lady. My late husband Michael used to say that there are some jobs that you just run to go and do, and I know that; it's a wonderful feeling. But there's also nothing better than a challenge. If you're on stage and it's not going well, the audience will tell you – by god they will. Sometimes it feels like they've got together in the foyer to decide not to laugh. But then it's wonderful, because it's like you're in the middle of a range of mountains and you think, ‘I'm not going to be beaten by this. I'm going to try and do it better.'”

Never stop being surprised by things “One of the most beautiful things I've ever seen was in Halifax, Nova Scotia while filming The Shipping News. Everything is extraordinary-looking there; the landscape is all monochrome white and pale grey – 50 shades of grey [laughs]. Once I was out for a walk and suddenly, around the corner of a headland, was this absolutely white, sparkling iceberg, and in the centre of it this pool of brightest blue – like a little lake of its own. I found out later it was a ‘growlerí – a bit thatís broken off a bigger iceberg. It was like seeing a Chekhov play and somebody pushing an enormous white skyscraper onto the stage.”

Fill your house with pets “I truly believe animals are good for the soul [Judi has owned four cats, two guinea pigs, 12 water voles, two goldfish, a hamster and two field mice]. One of my cats disappeared just before Christmas – he just went off, he was very old. But I also have Finty's [her daughter, 42] dog who lives with me and my legendary goldfish, Lazarus. I've had to give him the kiss of life twice, and he's still with us. That fish was the size of a finger when we got him. Now, he's bigger than a breadstick. Don't think for a second that I'm exaggerating. I know, because I had a bet with my daughter. I brought home a breadstick from the pub and Lazarus was the length of it and a little bit more.”

Selfridges is always the answer I love going shopping with Finty, we had a lovely day at Selfridges the other day. We ‘hit' Selfridges. I didn't buy anything, but I looked. Lovely, it was.

The Second Best Exotic Marigold Hotel is out in cinemas nationwide on 26 February