Cameron Diaz couldn't wait to play booze-swigging Miss Hannigan in the new remake of Annie, but the prospect of belting out the comedy villain's musical numbers had her welling up in terror.

"I cried," admits the actress, whose first experience of singing on screen came in a deliberately tone-deaf karaoke scene in 1997's My Best Friend's Wedding.

"In my defence, I had just done a movie in the Bahamas, working at night, flew home that morning, didn't sleep, and went into singing that very first afternoon. I was emotionally tapped, you know?"

Her megawatt smile fully reinstated after her ordeal, Diaz laughs as she confesses that the second time she cried about having to flex her vocal cords for the film, "there was no excuse - other than I was completely terrified".

Luckily, tomorrow was only a day away for the 42-year-old star (who is rumoured to be engaged to musician boyfriend Benji Madden, and is sporting an eye-catching ring on her finger).

"I knew that they were going to surround me with the best professionals and teachers, and they did," she adds. "They helped me to deliver a performance that was worthy of an autotune, so that was great!"

Singing jitters aside, it's clear Diaz loved every minute of playing Miss Hannigan.

"It's a wonderful, delicious role to play. You get to be this over the top villain while also making kids laugh, because you're more ridiculous than scary. Miss Hannigan is like the Wicked Stepmother or Captain Hook - even tiny kids get it - you want to see the hero kid beat the bad guy grown-up."

The rebooted version of the 1982 favourite sees parentless Annie (played by Beasts Of The Southern Wild actress Quvenzhane Wallis) living in foster care and being looked after - very badly - by Miss Hannigan, a bitter, money-grabbing, washed-up former pop star. The overall premise is the same, but with a modern twist.

Much-loved songs, like Tomorrow and It's A Hard Knock Life feature, but the wealthy Daddy Warbucks of the original film has been replaced by tough tycoon and mayoral candidate Will Stacks (Jamie Foxx).

When mobile phone mogul Stacks has a chance encounter with Annie, his campaign advisor decides that taking the youngster in could be a great way of winning votes. Over time, however, it's workaholic Stacks whose heartstrings get tugged at by all-singing, all-dancing Annie and her optimistic approach to life.

"It's a beautiful story," says Foxx (who, for the record, describes Diaz's vocals as "great"). "Annie comes into [Stacks'] life when he's just trying to use her as another rung up the ladder of success, but he finds out there's something inside her that he can't deny.

"Her love opens him up - that's a great emotion to be able to play on film."

He admits he was in awe of his young co-star Wallis, who has been nominated for a Golden Globe for her performance.

"You forget sometimes that Quvenzhane is only 11 years old, because she can handle the conversation with grown up folks and actually handle this workload," he says. "You have to be a special person, whether you're 11 or 57, to handle something like this. She's great."

Diaz, who previously starred alongside Foxx in the 1999 sports drama Any Given Sunday, jokes that she didn't find it hard to be mean to Wallis and her cute co-stars.

"I find it a really great opportunity to be able to yell at kids, without anybody telling me I shouldn't," she deadpans. "Most of my life, I get reprimanded or told, 'You shouldn't do that'. But now I get to do it. They got the right person for the job is all I'm sayin'."

As A-list stars with demanding filming schedules, the pair admit they can relate to Stacks' struggle to get the work-life balance right.

"It's so consuming; there are 12-hour days minimum, and you're [working] five days, sometimes six days a week and months at a time, and all other parts of your life can suffer and fall off a bit, so you can't really do all of it at once," says California-born Diaz.

"Definitely, there are times in my life when I'm like, 'Wow'. Last year was one of them - I did three movies back to back."

Father-of-two Foxx, 47, nods in agreement, adding: "It's the family. I think my oldest daughter [Corinne, now working as a model], it was tougher for her. All through my 20s, I just had to work all the time in order to stay afloat.

"But with my youngest daughter [Annalise, six], it's easier. She's able to come and hang out on set.

"That's the main thing you worry about, missing time with your family."

EXTRA TIME - NERVOUS SINGING STARS

:: Jennifer Lawrence - The Oscar-winning actress, who plays Katniss Everdeen in The Hunger Games films, sings in the latest instalment, Mockingjay - Part 1, and has admitted she cried nervous tears before filming the scene.

:: Carey Mulligan - The British star has revealed her Inside Llewyn Davis (2013) co-star Justin Timberlake made her laugh to ease her fears before she sang on set. "I was nervous about singing, but Justin was so sweet about it," she said.

:: Keira Knightley - The actress was "completely terrified" about singing in 2013 comedy drama Begin Again, in which she plays a singer-songwriter. "I found myself in a studio with real people who did it for a living and I was like, 'I don't know what I'm doing. I'm pretending'," she said.

:: Johnny Depp - In new musical film Into The Woods, Depp plays the Big Bad Wolf and has said of the Stephen Sondheim tracks he sings: "When you're not a crack vocalist, it's quite complicated stuff that he writes."

:: Eddie Redmayne - Now tipped for an Oscar for his role in The Theory Of Everything, Redmayne has confessed that when he successfully auditioned for a role in 2012's Les Miserables adaptation, it was "a horrible American Idol-style nightmare that involved singing these songs that you've grown up loving, to the people who wrote them".

:: Annie is in cinemas now