Jennifer Aniston Flaunts Cleavage, Long Legs in Sexy White Dress

Jennifer Aniston attends the 40th AFI Life Achievement Award honoring Shirley MacLaine held at Sony Pictures Studios on June 7, 2012 in Culver City, California. Credit: Christopher Polk/Getty Images for AFI

Is there any dress Jennifer Aniston doesn't look good in?

The actress, 43, made a surprise appearance at the 40th AFI Life Achievement Awards honoring her Rumor Has It costar Shirley MacLaine in Culver City, Calif. Thursday. Aniston wore a floor-length white Burberry gown with a cut-out back and thigh-high slit; she completed her ensemble with Tabita Simmons sandals and an ivory Valentino clutch.

The actress joined the night's honoree, 78, at the head table, where the two women sat beside Meryl Streep, 62, Melanie Griffith, 54, Julia Roberts, 44, and Sally Field, 65.

Despite being in the company of fellow A-listers, Aniston's presence didn't go unnoticed. "It took her a long time to even touch her salad because people kept coming up to the table to say hello and photographers kept coming by to take pictures," an onlooker tells Us Weekly. Eventually, "Jen ended up eating her whole entree: grilled fish with shrimp and some mixed veggies."

Later in the evening, Aniston's Horrible Bosses costar Charlie Day, 36, and his wife, Mary Elizabeth Ellis, 33, "came up to Jen and they hugged and talked for a while," according to the onlooker.

For MacLaine, the night was both a celebration of her illustrious career and the friends she's made along the way. "There are people here I haven't seen for years," she told Us. "I'm so excited!"

Other attendees included  John Travolta, 58, Katherine Heigl, 33, Dakota Fanning, 18, Jack Nicholson, 75, Morgan Freeman, 75, Mena Suvari, 33, Marcia Gay Harden, 52, Peter Fonda, 72, Lea Thompson, 51, Toni Collette, 39, and Elizabeth McGovern, 50.

AFI Life Achievement Awards air on TV Land June 24 at 9 pm.