Holliday Grainger and Harry Treadaway started their family with newborn twins.
Like his own twins, Harry is also a twin himself with actor brother Luke.
The high-profile couple were spotted breaking cover for the first time with their babies in tow in Devon last week.
It's the first time they have been seen since the babies were born recently.
They made the move to Devon from London when they found out Holliday was pregnant last year.
The Borgias actress Holliday, 33, and Harry have been romancing since they first fell in love in 2015.
Now the couple have become parents for the first time.
Seen in pictures on MailOnline, the lovebirds enjoyed a low-key stroll with their newborn babies.
"It was a lovely, happy family outing," said an onlooker told the newspaper.
"Even though both of the actors are on our TV screens all the time, no one paid them the slightest bit of attention.
"But the twins got a lot of admiring comments from groups of old ladies. Mum and Dad seemed delighted by that."
They keep their romance low-profile, despite both being famous in their own rights.
Most recently, Holliday has been playing Detective Inspector Rachel Carey in The Capture.
She has built up a huge fan base with her detective role.
It's believed a second series for The Capture has been put off because of her pregnancy, according to the newspaper.
She has had many noteworthy roles including playing Lucrezia Borgia in The Borgias alongside Jeremy Irons.
As well as TV roles, she has had great success with her movie titles.
Among her movie titles she played the cold leading lady Estrella in the 2011 adaptation of Great Expectations.
