Jennifer Aniston throws birthday bash for Justin Theroux

OHMYGOSSIP — Jennifer Aniston threw a star-studded birthday party for her fiance Justin Theroux at their $21 million Bel Air mansion on Saturday, Aug. 10. Guests including Ben Stiller, Isla Fisher, Sacha Baron Cohen, Dax Shepard and more enjoyed celebrating Justin’s 42nd birthday.

Before the party, the ladies got ready inside (Aniston’s hair stylist Chris McMillan was on hand to style the former Friends star), while Theroux, an actor-screenwriter, hung out with his guys outside, reports Us Weekly.

“Several of Justin’s friends spent the afternoon at the house hanging out by the pool with him and celebrating his birthday,” an eyewitness said.

“It was a relaxed afternoon and they were all in the cabana area having drinks and listening to music like Kanye West and The Kinks.”

Other attendees included Lake Bell, Will Arnett, Laura Dern, Ellen DeGeneres, Portia de Rossi, Tobey Maguire, Jen Meyer, Jimmy Kimmel, John Krasinski, Emily Blunt, and Jason Bateman.

“Most people were dressed casually in jeans and T-shirts,” the source said. “Justin was dressed casually in a black T-shirt and black jeans, and Jen had on a short green skirt and long sleeved top.”