Armie Hammer and his wife, TV host Elizabeth Chambers, are expecting their first child Credit: Jeff Vespa/WireImage

Armie Hammer's social network is about to get a little bigger! The Lone Ranger star and his wife, Elizabeth Chambers, are expecting their first child together later this year, his rep confirms to Us Weekly.

"They talk about having a couple, though they're thrilled with one now," a source tells Us of the parents-to-be. "They treated their dog as a good warmup."

The Social Network actor, 27, also got some valuable experience at the May 18 Kids' Art Museum Project event at Hammer Museum, where he read Oh, the Places You'll Go by Dr. Seuss. "I'm practicing for when I do have kids," he told Us, though he played coy on when that might be. "If it happens, it happens," he teased.

Hammer and his TV personality wife, 31, have been married since May 2010. He'll next appear in the big-screen adaptation of The Man From U.N.C.L.E.