He played the lead in Angelina Jolie's Unbroken
Despite being far from a household name in the US, Jack beat off stiff competition to win the role of US athlete Louis Zamperini, who was captured and sent to a Japanese detention camp during World War II.
His audition for Angelina was pretty intense
This wasn't just a read-a-few-lines-to-camera jobby. To re-enact the POW camp conditions, Jack was asked to sit in a tiny cell, not knowing whether he would be there for an hour or a few minutes, while a crew member came in at random times to hit him with a rubber baton. "All of the actors were so brave and many of the auditions were emotional and heartbreaking" said Jolie, "and then came Jack. He went in the cell. He sat in the dark. He didn't force anything. He didn't act. He was just present… when he was hit he took the beating, he ended up shaking from the feelings and he allowed his emotions to come forward."
Filming wasn't exactly a cake-walk either...
To simulate the malnutrition Louis and his fellow soldiers would have endured marooned on a life raft before being captured by the Japanese, Jack and two of his co-stars had to subsist on a strict 500-calorie-a-day diet for two whole months. Like being on the 5.2, but with no 5. We'd be VERY grumpy monsters if anyone made us do that.
He's originally from Derby
Late last year he was presented with the 'New Hollywood Award' at the Hollywood Film Awards (to give you an idea of what a big deal this is, Lupita N'yongo won it last year), At the ceremony Angelina even did a bit of Derby slang in his honour. "It is my privilege to present the New Hollywood Award to the least Hollywood person I know… straight from Derby, ah up me duck, Jack O'Connell!"
He used to be on Skins
Jack is yet another member of the Skins alumni to make the big leap across the pond (see also Kaya Scodelario and Nicholas Hoult), his other TV credits include East End drama The Runaway and The Bill.
He dated Tulisa
They had a three month romance in 2012 when Tulisa was on The X Factor but broke up blaming "incompatible work schedules."
And he's pals with Cara Delevingne
Cara and Jack are starring in upcoming 17th century drama Tulip Fever together and have become close pals on set. The rumour mill went into overdrive when Cara instagrammed a picture of some love bites on Jack's neck earlier this month - though we suspect the pair are just good friends.
Next up George Clooney?
The Angelina endorsement appears to have opened some very A-list doors. Next up Jack is rumoured to be starring opposite George Clooney and Julia Roberts in Money Monster. Wowzer. From Derby to Hollywood. This guys is about to become very, very famous.
By Lucy Pavia / @lucypavia