The Hollywood star's wife Amelia Warren - who he married in April - gave birth to the couple's daughter last month, a rep has confirmed to People magazine.
The rep said: "[Jamie and Amelia] are delighted to announce the birth of their daughter, born at the end of November."
Northern Ireland native Jamie is currently filming in Vancouver for the screen adaptation of EL James' hugely successful erotic book, in which he has been cast as the notorious Christian Grey.
He was offered the highly-anticipated role of Christian after original cast member Charlie Hunnam dropped out in October.
Also appearing in the Fifty Shades film are actress Dakota Johnson, who will play female lead Anastasia Steele and British singer Rita Ora, who has bagged the role of Mia, Christian's sister.
Find out more about 31-year-old Jamie here.
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