Mia McKenna-Bruce calls Helena Bonham-Carter "mum"

Mia told The Sunday Times' Culture magazine: "She calls me 'daughter' and I text her, like, 'Hey Mum'.

"[She's taught me] to advocate for myself ... it's OK to say you need something."

Helena, 59, always carries a basked of snacks and drinks, including dried mango and smoothies for energy, and Mia has begun doing the same.

She noted: "Now I've introduced a snack situation."

The Persuasion actress has been cast as Ringo Starr's wife Maureen in Sir Sam Mendes' upcoming Beatles biopics and she already views co-stars Barry Keoghan, Paul Mescal, Harris Dickinson and Joseph Quinn - who play the Fab Four - as "brothers".

She said: "[I was one of the first cast] so I spent a lot of time early on with all the boys. They're all like brothers, like silly boys, in a good way."

Asked which of the quartet has the best voice, Mia was reluctant to answer before offering praise for her on-screen husband.

She said: "Barry. I'll support my Baz."

Because of her role in the biopics, Mia has found people are keen to share their Beatles stories with her.

She said: "Someone described her as the person who, if she went to a party, would be the one that would go up to the person who was on their own. She had a huge heart...

"A lot of people come up to me and share their stories about the Beatles now."

Meanwhile, the How to Have Sex star and her husband Tom Leach have a two-year-old son Leo together and while she adores her little boy, Mia admitted starting a family in her 20s wasn't "overly planned".

She said: "I can't say it was overly planned ... it's not easy, don't get me wrong. But it's magic."

Mia is grateful for the support of her family and friends when it comes to juggling motherhood with her career.

She said: "It's an all-hands-on-deck situation."