Lia Smith was positively radiant at her Jan. 4 wedding to Justin Bartha -- and now we know why! The blushing bride got a little extra glow from being pregnant, a source confirms exclusively to Us Weekly.
Smith, a personal fitness trainer, said "I do" to the "Hangover" actor in Hawaii, at the picturesque Kualoa Ranch. An onlooker tells Us she "had her hand on her stomach most of the time" and "looked like she had a little bump" under her flowy white gown. Later, at the farewell brunch, she donned a loose-fitting dress and touched her belly as she walked around.
Engaged since May 2013, the parents-to-be exchanged vows in front of pals including Jesse Eisenberg, Ken Jeong, and Reese Witherspoon. After the ceremony, an eyewitness says, the bride and groom posed for photos with their families as guests enjoyed cocktails in the great outdoors. (Smith sipped on a clear beverage with lime.)
This will be the first child for the couple, who first met during a Pilates session at Equinox in L.A., where Smith is an instructor. They took their relationship public in January 2013, and Bartha -- who previously dated Ashley Olsen for two years -- popped the question at Post Ranch Inn in Big Sur, Calif., just a few months later.
"She was completely surprised by the whole thing," a source told Us of the proposal. "The trip to Big Sur, the engagement, the ring, everything. So cute."
"They are an amazing couple," the insider added of the 35-year-old actor and his now-wife, "and so gorgeous together."
MORE FROM WONDERWALL: