At the L.A. premiere of "Hit and Run" on Aug. 14, Cooper, 37, was asked about the actress' recent engagement to Justin Theroux, her love of 18 months. "That's awesome!" Cooper told Us Weekly. (The two starred in 2009's ensemble rom-com "He's Just Not That Into You" but did not share any scenes.)
(Reps for both Theroux, 41, and Aniston, 43, confirmed the stars' engagement to Us on Aug. 12; Screenwriter Theroux's rep added, "Justin Theroux had an amazing birthday Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage.")
Cooper and Aniston were first spotted dining together at New York City's Il Cantinori on June 18, 2009. When Cooper and his "Case 39" costar Renee Zellweger, 43, decided to amp up their romance, Aniston was disappointed, a source told Us at the time. "She wanted to turn her date with Cooper into something."
All that is water under the bridge now. According to an insider, Theroux -- who first met Aniston via mutual pal Ben Stiller on the 2007 set of "Tropic Thunder" -- "makes her feel safe and secure when she's with him. A lot of her insecurities melt away."
And Theroux, who costarred with Aniston and Paul Rudd in "Wanderlust," is the perfect match for once-wed Aniston. "He's a charming young man," the "Friends" star's father, "Days of Our Lives" actor John Aniston, told Us in late 2011. "I think they make a wonderful couple."