Keri Russell's co-star has confirmed her pregnancy.

Keri Russell and Matthew Rhys

Keri Russell and Matthew Rhys

It has been rumoured for several weeks that the actress is expecting a baby with co-star Matthew Rhys.

And now Noah Emmerich, who stars with the pair in hit television show 'The Americans', has revealed the happy news is true.

Speaking during the FX TCA winter press tour, Noah told Entertainment Tonight that Keri's pregnancy will not be written into the show.

He said: "First of all, Keri's really petite. It looks like she swallowed a large pea. But yes, we shoot around it.

"She's always standing behind a huge counter with a toaster on it. No, there's only a few angles where you can see it. It's fixable - just picking your shots."

Keri is already mother to eight-year-old River and four-year-old Willa with ex-husband, Shane Deary, who she divorced in 2013.

Matthew and Keri were rumoured to be dating for some time but deflected questions about any romance until they finally made their first public appearance as a couple in April 2014.

And Matthew, 41, couldn't be more smitten with Keri.

A source told Us Weekly magazine: "They are always together and love roaming around New York.

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