Dame Judi Dench told a "really dirty joke" to put Isla Fisher at ease.

Isla Fisher

Isla Fisher

The Australian actress admitted it was an intimidating prospect to be sharing scenes with "our greatest living actress" in 'Blithe Spirit' but the 86-year-old screen legend understood her nerves and helped her to relax.

Isla said: “I had to film two really big scenes with her and I kept saying to myself, ‘Fisher, don’t you forget your lines!'

“And it was almost like she picked up on that energy, and she made a really funny dirty joke that put me right at ease. She’s got the most fantastic sense of humour. From that moment on I just relaxed and it was a masterclass, watching Dame Judi Dench perform.”

The 45-year-old star - who has daughters Olive, 13, Elula, 10, and six-year-old son Montgomery with husband Sacha Baron Cohen - and her brood recently returned to her native Australia and the 'Now You See Me' star is much more at ease there than anywhere else in the world.

She said: “I feel like I can be myself in Australia. “I love the people. I love the colours and the sights and the taste and the smells. And there’s something about being home which is just … it feels very magical.

"I miss it so much when I’m away and I have a very Australian sensibility. Whenever I meet another Aussie, I always think, ‘Oh my gosh, we’re twins!’”

Isla is keen for her kids have a "normal childhood" so although she loves talking about motherhood, she won't do so in public.

She told Australia's Marie Claire magazine: “Motherhood is actually my favorite topic, but I keep it private.

“I think all parents are trying to protect their kids, especially in the social media age. I want our children to have a normal childhood – being able to play outside without pressure or scrutiny. All kids have the right to just be kids, and I would never sell a film or magazine by speaking about [mine]."