Looks like Marcus Mumford is about to have an actual Mumford son ... or daughter.

According to Us Weekly, cute-as-a-button actress Carey Mulligan is reportedly expecting her first child with her lead-singing hubby, to whom she's been hitched for over three years.

Carey, who hit the Tony Awards on Sunday (June 7) in NYC, was wearing a conspicuously loose-fitting gown, and from some angles one *might* contend there was a little bump action going on there. Might.

But Mulligan has been playing the hide-the-baby game very well over the last few weeks because there was barely any sign of mini-Mumford-to-be on the early May Met Gala red carpet at all. Which means her stylist has been very well trained in the art of keeping mama's news mum.

Mulligan was nominated for Best Actress at the 2015 Tony Awards for her part in "Skylight," opposite Elisabeth Moss, Ruth Wilson, Geneva Carr and the night's winner, Helen Mirren.

"They weren't planning on announcing, but she hasn't stopped working," a source told Us Weekly. "Everybody around her is being very supportive. The show ends soon and they're going back to England after."

Congrats to the happy couple!