Keri Russell and Matthew Rhys have welcomed their first child together.

Keri Russell and Matthew Rhys

Keri Russell and Matthew Rhys

The 40-year-old actress gave birth last week and she and Matthew, 41, could not be happier.

A source told Us Weekly: "Keri and Matt both look overjoyed and are over the moon to be new parents. They are always snapping pictures of the baby, and family and friends have been sending gifts.

"Keri's mother and brother have been staying with them for the last week, spending all their time doting over the baby."

Keri already has son River, eight, and daughter Willa, four, with ex-husband Shane Deary - and this is her first child with her 'Americans' co-star Matthew Rhys.

The couple were reported to have been dating for some time but deflected questions about any romance until they finally made their first public appearance as a couple in April 2014.

A source previously said: "They are always together and love roaming around New York.

"Matthew is really in love. They feel they should have always been together."

Keri previously said she enjoyed the "freedom" of her role in the spy drama, in which she and Matthew play KGB agents posing as a married American couple.

She said: "It's not this big sweeping romantic movie where you have to be so in love and so beautiful and so sexy.

"You're usually using the sexuality, at least in the spy end of it, to get something.

"So there is kind of a freedom in that, because it's kind of messier or more direct than that."