Her character Nebula was originally supposed to be killed off in the first instalment of the movie, a surprise £600million box office hit in 2014.
But director James Gunn was so impressed with Karen — who shaved off her auburn locks to play the bald-headed cyborg — that he not only saved her but gave her the lead role in volume two.
“I’m here because there are lots of opportunities career-wise. “There are parts in the UK too, but they’re mostly period dramas.” Instead of getting typecast she took her dad Ray’s advice to shun the glamorous parts and sought out gritty, sinister roles — like Marvel’s blue-skinned Nebula. “My dad used to tell me when I was younger, ‘You don’t want to be a Bond girl — you want to be a villain’.
It is an astonishing feat for a 29-year-old who was known for her chaotic partying while playing Amy Pond on the BBC1 show, which she joined in 2010.
One insider told The Sun: “Karen’s not known as a party person and certainly not by LA standards, where most young actors and actresses use after-hours parties as a way of meeting producers and directors.
“She may have been into that years ago but now she’s a complete homebody.
And most recently, it led her to America in search of new challenges.
She declared on arriving: “I’m not here on holiday.
Back then, she was often snapped slumped in the back of taxis or tumbling out of trendy London nightspots like The Box.