Jennifer Aniston Engaged To Justin Theroux

Theroux popped the question to his 'Wanderlust' co-star on his birthday on Friday.

Jennifer Aniston and her beau, fellow actor and screenwriter Justin Theroux, are officially engaged.

His rep confirmed the news to People in a statement, "Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage."

They sparked engagement rumors in March when Aniston was spotted in New York City wearing what looked to be a shiny piece of jewelry on her ring finger.

The "Wanderlust" co-stars began dating in May 2011. While the pair met on the set of the film, in an interview with "Good Morning America," Aniston clarified nothing romantic happened while shooting the comedy. "Nothing happened on that movie. ... It's a rumor. It's the easy rumor, but nothing happened. We were just friends," she said. "I've known Justin for a long time. He is really cute [and] he's a great actor."

This is the first marriage for Theroux and the second for Aniston, who was famously married to Brad Pitt. The two already have a dog named Sophie, and Aniston has said she might want to add kids to the mix.

"I think people maybe want me to have a kid now. I still kind of go with it," Aniston told GQ. "If it happens, it happens. I'm calm and peaceful with whatever the plan is. It's not something where I'm going, 'I gotta have a kid!' "

During our "MTV First" with Aniston earlier this year, she talked about what it was about her "Wanderlust" that caught her eye.

"What I think is so awesome about Justin is that he really just disappears," she added. "He sort of morphs into things, into characters and also has a leading-man quality, which I think is beautiful. He's just great."