Lead by actress Teri Hatcher, a slew of celebrities were on hand yesterday (September 12) to work up a good sweat for charity as they participated in the Malibu Triathlon.

The annual event includes a half-mile ocean swim, 18-mile bike ride, and a four-mile run. Teri participated to raise funds for the L.A.’s Children’s Hospital.

Competitors in the celebrity division also include Felecity Huffman, Mario Lopez, David Hasselhoff and Entourage actor Jeremy Piven.

Last year, the event raised nearly a million dollars for the hospital’s Pediatric Cancer Research Program.

Before taking on the day-long challenge, Teri wrote on her site: “Every step and stroke will be motivated by you. If I even think about giving up, I’ll think about you. So thank you again. This has been an amazing experience of support and community. I’m addicted to both the race and the fundraising. I will try so hard not to fail you!”