Jennifer Lopez was one of several celebrities to complete a triathlon in Malibu, CA today, showing off her shapely post-pregnancy body just seven months after giving birth to twins.

The singer, 39, threw her arms in the air and smiled to onlookers as she crossed the finish line of the grueling event, which involves swimming, running and biking. People magazine reports she finished the race in 2 hours, 23 minutes and 28 seconds. On the sidelines to offer support were fans and Jennifer's husband Marc Anthony, who kissed his wife between the biking and running portions of the race.

After finishing, Lopez joined family and friends in a VIP area where actors Matthew McConaughey and Jon Cryer were also spotted. McConaughey was with his girlfriend Camila Alves and their newborn son Levi.

J.Lo's triathlon performance comes just days after "Project Runway" host Heidi Klum revealed that the singing sensation had pulled out of a planned appearance on the season finale of the fashion designers show due to a foot injury.

The New York Daily News reports that Lopez and her family were quickly leaving L.A. so they could focus on a 40th birthday bash being held for Marc Sunday night at a New York hotel.