Ioan Gruffudd and Alice Evans have become parents to their second daughter.
The British stars, who met in 2000 on the film 102 Dalmations, already have a four-year-old Ella Betsi.
They said in a statement to E! News: "We are beyond thrilled to announce the arrival of our daughter, Elsie Marigold, on September 13th. A little sister for Ella Betsi.
"We both feel very grateful and very blessed."
The baby was due on September 25 but arrived early in Los Angeles, where they now live.
The Fantastic Four actor, 39, and Alice, 42, married in Mexico in 2007.
Welsh star Ioan previously told the Daily Mail: "We'd wanted a baby for a while and after it didn't happen for us naturally we said, 'Let's take what science has to offer.' Luckily for us, it worked the first time so it wasn't a long, hard struggle."