The 29-year-old actress and husband Laurence Fox "couldn't be happier" after welcoming their second child into the world on Thursday, and the actor has taken to twitter to reveal everything is "fine".
He tweeted: "One born every minute. We had our minute today. Couldn't be happier. Beautiful boy. Everything fine."
The couple - who also have three-year-old son Winston - are yet to reveal a name for their latest addition to the family.
Following the birth, the former Doctor Who beauty's sister Ellie also tweeted her congratulations to the pair.
She wrote: "Would like to say welcome new licckel baby boy I love you so much already can't wait so kiss those big lips :) x (sic)"