By Breaking Celebrity News Staff

Jen Aniston is getting married!

She and Justin Theroux became engaged on Friday, his 41st birthday.

"Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage," his rep said.

The couple has been dating since early last 2011, although Jennifer's said they've known each other "for years."

This will be Jen's second marriage. She and Brad Pitt divorced in 2005.