The gala, which honoured Ed Ruscha and Stanley Kubrick and was presented by Gucci, featured a host of Hollywood stars.
Aniston wowed in a slinky black silk evening gown which featured satin panelling and a plunging neckline that almost reached her navel.
Theroux also dressed to impress in a classic tuxedo.
Aniston flashed her huge engagement ring at the event as she posed with actress Salma Hayek, who attended the event with her husband of three years, French businessman, Francois-Henri Pinault.
Twilight star Robert Pattinson made a surprise solo appearance, and was pictured with singer Florence Welch, who performed for the starry audience with her band Florence and the Machine.
Cameron Diaz also made an appearance at the event, wearing a demure yellow silk dress and a statement necklace.
British actress and model Rosie Huntington-Whiteley stunned in an emerald floor-length evening gown which featured a ruffle-neck and cutaway sides.
New parents Drew Barrymore and her husband Will Kopelman showed Aniston and Theroux photos of their newborn daughter Olive.
Cameron Diaz poses with friend Jennifer Aniston at the event.