01/29/2014 at 07:00 AM EST
isn't letting her recent split from bodyguard boyfriend
Martin Kirsten keep her down.
The supermodel, 40, stepped out Tuesday night for a good cause, the Hollywood Stands Up to Cancer event presented by the Entertainment Industry Foundation, hosted by event chairs Jim Toth and wife Reese Witherspoon
Other high-wattage stars attending included Gwyneth Paltrow
and Chris Martin, Drew Barrymore
and Will Kopelman, and Anne Hathaway
and Adam Shulman. Enjoying performances by John Mayer
– there with girlfriend Katy Perry – Christina Aguilera
and Jamie Foxx.
Looking stunning in a slim-fitting brown long-sleeved dress with her hair down, Klum was all smiles and the very first celebrity guest to arrive. Stand Up to Cancer
is a cause she has long supported.
"They asked me to do the photos for their campaign and we always did them quite cheeky – I wasn't wearing much," Klum exclusively told PEOPLE at the event. "But I just think it's important to give your time to important organizations like this."
Asked if having kids changed her outlook on helping others, the mother of four said, "To be honest I always wanted to help, whether it was supporting cancer research or supporting AIDS research with Elton John, I did that before having children. When you're in the paper and people listen to what you have to say, that [helping others] is part of what you have to do as a human being."
During the event, Klum stuck close to a girlfriend and happily obliged when attendees asked for her to pose for personal photographs.
As part of the presentation, Stand Up to Cancer announced the Jim Toth Sr. Breakthrough Lung Cancer Research Award in honor of Toth's father, who succumbed to lung cancer.
A new collaboration between SU2C and the American Cancer Society was also announced, with the first significant research project to focus on lung cancer.