Credit: Jemal Countess/Getty; Jamie McCarthy/

Facing the cameras for a good cause.

Heidi Klum was one of the brightest shining stars on the red carpet at Wednesday's amfAR gala at Cipriani Wall Street in Manhattan. In her first official event since she and husband Seal announced their separation, the supermodel, 38, stunned as ever in a Roberto Cavalli gown, Lorraine Schwartz jewelry -- and with her yellow diamond wedding ring still conspicuously on her finger.

In a low-key mood (smiling a bit less brightly than usual), the mother of four avoided press interviews on the red carpet, which was also graced by celebs like Sarah Jessica Parker, Jennifer Hudson, Cindy Crawford, Lindsay Lohan and Padma Lakshmi. See more photos from Klum's first big outing.

Klum changed out of her gown into a sexy, asymmetrical pantsuit to host the afterparty at hotspot Double Seven, arriving after most of the other guests.

Sticking to the VIP booth, Klum played the gracious hostess throughout the evening, tending to her pals, and even standing up and dancing to the tunes. A camera crew from Germany's Next Top Model, which she hosts, followed Klum for the bash.

"Heidi is trying to focus on work and her kids in this time of heartbreak," a source says of the star, whose estranged husband Seal 48, has been chatting up their split to the press as he promotes a new album. "She most definitely wouldn't be out tonight if it wasn't to support a charity she believes in."

Another source adds the couple (married for seven years) "have zero plans to get back together."