Keri Russell, co-star Matthew Rhys expecting first child

LOS ANGELES, Jan. 7 (UPI) -- Keri Russell and boyfriend Matthew Rhys are reportedly expecting their first child.

Sources told People magazine the 39-year-old American actress and 41-year-old Welsh actor are "thrilled" about Russell's pregnancy.

"Keri is more than four months along," an insider told Us Weekly. "It's so exciting for them!" another source added. The couple have yet to comment on the reports.

Russell and Rhys co-star as Elizabeth and Philip Jennings on FX series The Americans, and went public with their relationship in April 2014. The actress is already mother to 8-year-old son River and 4-year-old daughter Willa with ex-husband Shane Dreary.

"I like working hard, but my life outside of my career is equally important to me," Russell told Parade magazine in 2013. "You instantly become less selfish [when you're a mother]. You can't be the biggest person in the world anymore -- they are. It really grounds you."

The Americans premiered in 2013, and will return for a fourth season in March. The series follows two Soviet KGB officers (Russell and Rhys) posing as an American married couple, and follows the pair in their personal and professional lives.

"It's not this big, sweeping romantic movie where you have to be so in love and so beautiful and so sexy," Russell previously said of her on-screen romance with Rhys. "You're usually using the sexuality, at least the spy end of it, to get something. So there is a kind of freedom in that, because it's kind of messier or more direct than that."

Russell is best known for playing Felicity Porter on The WB series Felicity, and will next star in Free State of Jones with Matthew McConaughey. Rhys portrayed Kevin Walker on ABC drama Brothers & Sisters, and will appear in Jungle Book: Origins with Benedict Cumberbatch.