Baby on Board!

Rooney Mara and Joaquin Phoenix vegan bun in the oven! The have a fiancés are expecting their eco-conscious source tells Us: first child together, a Phoenix, “Rooney is six months pregnant.”

45, is already proving he’ll be a dad. “Joaquin’s great,” says the doting accompanying her to source. “He’s been it’s unclear doctor’s

when they’ll wed, appointments.” While “are so in love,” adds Mara, 35, and Phoenix

an insider. Congrats!