Gavin and Stacey star Joanna Page is expecting her fourth child with her actor husband James Thornton.
Joanna shot to fame in the role of Stacey Shipman in the hit BBC comedy, which first aired in 2007.
The 44-year-old actress, who also appeared on screen in the 1999 series David Copperfield, revealed the news on Instagram with a picture of her small baby bump.
"Well, this is a surprise!!" she wrote. "Baby number 4 on the way! It's going to be a busy Christmas!"
She accompanied the image with a smiling and party emoji, as well as the hashtags "#pregnant" and "#babyontheway".
Joanna and James already have three children, with daughter Eva born in 2013, and sons Kit and Noah following in 2015 and 2016.
The new revelation was met with delighted reactions from fellow celebrities, with TV presenter Denise Van Outen and former Coronation Street star Catherine Tyldesley offering their congratulations.
Last year, Joanna told The Sun that she and her husband threatened to divorce each other because they were arguing during the first lockdown - including not speaking for a month - because they could not hook up.
"We came out of that a bit numb and deadened and desperate for anything we could get because we just argued so much," Joanna said. "'Let's get some sex in before we have to pick the kids up from school' - that's how desperate we'd got.
"I'm sure all parents found it really difficult during lockdown. You're with the children so much, and then at night time they all just wanted to sleep in bed with us."