Theroux proposed to the former "Friends" star Friday, which happened to be his 41st birthday and was delighted when the 43-year-old actress said yes, reports people.com.
"Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage," Theroux's representative told people.com.
The news comes just days after rumours of their split emerged.
This will be Theroux's first marriage, while Aniston was previously married to actor Brad Pitt. They split in 2005 after four-and-a-half years of marriage, and Pitt is now engaged to actress Angelina Jolie.