Being Alexandra Burke must be exhausting. After an hour in her company, I felt like I needed to have a nap and run a marathon simultaneously.
To explain, Burke (29) is rehearsing for the first major West End revival of Chess since it opened in 1986, fresh from releasing an album and her well-publicised stint on Strictly Come Dancing.
Today she's been up since 6.30am, having rearranged her evening gym session to fit in after-work drinks with her English National Opera castmates, and just before our interview she performed the all-time classic I Know Him So Well in front of the company for the first time.
She cuts a calm, unassuming figure, talking as if we've known each other for years. When I tell her I need whatever she's having, she replies: "Oh babe. It's Berocca!"
Burke's role as Svetlana, in the midst of the musical epic about Cold War superpowers facing off in a chess championship by Benny Andersson, Bjorn Ulvaeus and Tim Rice, cements the reputation she's carved as a London theatre treasure since winning The X Factor 10 years ago. She then had lead West End roles in The Bodyguard and Sister Act.
She reflects carefully on decisions around her career, but found herself saying yes to Chess within 30 minutes. All it took was one phone call with director Laurence Connor. "I said, listen, I don't know much about Chess, but there's something about the way that you're describing it that makes me feel like this is going to be the best opportunity for my life," she says with sincerity.
The production will be a personal challenge - it's her first time doing eight shows a week - but she's endearingly starry-eyed about being a part of it, talking with disbelief about what's going on in rehearsals: "Honestly, the notes that came out of these people's mouths ... I had to check myself, 'What, where am I? What am I doing? Why are they so amazing?'"
Another mark of the show's importance for Burke is that co-star Michael Ball, renowned statesman of musical theatre, told her that singing Chess has been one of his dreams, "so that's how you know".
Burke describes Svetlana, the estranged wife of Ball's character, Anatoly, as "an independent woman looking after her child", but she has "deep heart-break to her". Why? "Because all anyone wants in life is to make sure their marriage is safe, and to make sure they've got a child that they bring up in a happy home."
It's something Burke wants. She tells me she creates mood boards to visualise her hopes for the next three years, and the current one features babies and weddings (she met fiance Josh Ginnelly while working on The Bodyguard where he was a stage manager). But it's for "one day, - not any time soon".
She's worked 10 years flat out and wants to do a few more before taking a break - an indefatigable work ethic that makes me wonder what it's all for.
"It's a mental thing for me. I have to stay busy," she confides. "I suffer from anxiety and panic attacks quite badly. In recent times it's got worse."
She's also "trying to avoid thinking about my reality most of the time" -her mother, Soul II Soul singer Melissa Bell, died last year at the age of 53.
Tears form in her eyes when I ask her if she ever takes a day, just for herself - "not really" - but then she smiles again, remembering a rare day off on Easter Sunday, spent with her family. She shows me videos of her brothers dancing the jive (Burke spent an hour teaching them, and they're pretty impressive), while her nieces and nephews pretended to be the Strictly judges.
"I'm such a home person. Honest to God, I'd give anything just to go home and sit and chill on the sofa with the dogs," she says.
Her mother used to take her to posh Bishops Avenue in London every weekend - "She said, 'Visualise yourself in one of those houses, this is the dream'. And I bought a seven-bedroom house."
Her mother's death - and life - inform everything about Burke's spirit. Life's too short not to enjoy your achievements, she thinks. "In Britain, we're very polite. It's very, 'I'm sorry'. It's very, 'Do you want a cup of tea?' It's too polite sometimes. Why can't you be proud? If there's something you're good at, you could inspire somebody else to be great at something as well."
But this ethos is also informed by something more urgent. "I'm gonna make the most of my life because every single woman in my life has died young," she tells me. Donna Summer - another woman who "died so bloody young" - is Burke's dream role, and there's a musical opening on Broadway now. Could it be London-bound? I hope Burke gets the role. But I hope she gets a day off first.
Chess is at London's Coliseum (020 7836 0111, eno.org) until June 2