Video posted on the actor's YouTube page shows him pranking members of Gold's Gym in Venice by posing as a physical fitness trainer.
"I'm Howard Kleiner. I'm here to help you," Schwarzenegger says in the YouTube video. "When it burns, it grows. Remember that," he tells a woman at the gym.
Schwarzenegger hopes the video raises awareness and money for his After-School All-Stars program. ASAS provides nationwide after-school care to low-income families.
According to the program's website, ASAS was founded in Los Angeles in 1992 with 40,000 youth competing in summer time athletic and academic competitions. It has since provided comprehensive out-of-school time programs to 92,152 participants at 346 schools.
Donors who donate at least $10 to the program are automatically entered to win a chance to ride shotgun with Schwarzenegger in his own personal Sherman tank. The contest includes flight and hotel accommodations for two in Los Angeles.
Schwarzenegger is matching every donation dollar for dollar.
The contest ends on Jan. 31. The experience will take place in late February or early March 2014.
For more information or to enter the contest, visit www.omaze.com/arnold.