"I am a quiet person's nightmare. The only time I shut up is when I'm reading, because I'm a book geek," she told the Daily Mail in 2010.
"I was the attention-seeking child in class who needed everyone to look at meee. Luckily that got channelled into acting, because I would have been terrible at anything else. I would have been a nightmare in any kind of office, because I wouldn't have had any friends in any environment other than performing. I'm quite loud and quite overconfident - I'm a vain 27-year-old actress."
2. She loves 'obscure Chinese documentaries'
Whittaker was described as a "film buff" in a 2011 interview with the Guardian after displaying a nerdy knowledge of "everything from Molly Ringwald, Young Guns and The Goonies to obscure Chinese documentaries" with the writer.
In 2010, she was part of the British Independent Film Awards judging panel, when she wasn't filming Elephant and Castle-based sci-fi spoof Attack the Block or anthology TV series Accused.
3. She's maintained starry company since drama school
Whittaker trained at Guildhall School of Music and Drama, which she applied to instead of university, and studied alongside Captain America's Hayley Atwell and Michelle Dockery, best known for her work in Downton Abbey.
She made friends with Gemma Arterton after the pair were cast in the BBC's adaptation of Tess of the D'Urbervilles, and both were reunited in St Trinian's, released a year later in 2007 in which Whittaker played Rupert Everett's secretary Beverly.
4. Her code name for Doctor Who was 'The Clooney'
With such feverish anticipation over who would play the new Time Lord, Whittaker was sworn to secrecy over the role that could come to define her career.
Such secrecy, in fact, that it wasn't even spoken about in the household she shares with her husband, American actor Christian Contreras.
"In my home, and with my agent, it was The Clooney," she told fan site Blogter Who.
"Because to me and my husband, George is an iconic guy. And we thought: what's a really famous iconic name? It was just fitting."
5. Whittaker filled in for Carey Mulligan with just two hours' notice
When Mulligan contracted appendicitis mid-way through the run of The Seagull at the Royal Court in 2007, it was Whittaker who was called upon with just two hours' notice after originally auditioning for the role.
"I've never been so scared in my life, it's like your worst nightmare, walking on stage and not knowing your lines. I got a phone call at 5pm. Can you do this?" She told the Independent."I was actually more concerned that I'd not had my tea."
When Mulligan returned to health, Whittaker was nothing but gracious, saying: "Carey powered back to health after a few days - she was an absolute warrior. And when I saw her on stage again, I realised why I hadn't got the job in the first place."
6. She starred alongside her husband in an award-winning indie comedy
Whittaker's last film credit was in Adult Life Skills, a homespun comedy written by her friend Rachel Tunnard (who also appears in the film) that won the Nora Ephron Prize at Tribeca Film Festival in 2016.
It sees Whittaker speak with a northern accent not far from her own as Anna, a 29-year-old grieving for her twin brother and living in a shed at the bottom of her mum's garden. Contreras appears as Hank, a potential suitor.
