You're standing in a public park, and a stranger hands you a cell phone -- it rings. Do you take the call?
That's just what Jason Bourne star Matt Damon secretly asked bystanders in a Los Angeles park to do when he teamed up with Omaze for a prank aimed at raising money for Water.org, a non-profit the actor founded that works to provide clean water to developing countries.
As you can see in the video below, not everyone is game for the challenge -- one man very hilariously rolls his eyes and casts the phone aside -- but several people actually agree to follow Damon's ridiculous instructions, eventually being guided to a room where the 45-year-old Oscar winner greets the participants and lets them know they've won tickets to the premiere of the newest Bourne film, which is set to hit theaters on July 29.
WATCH: Matt Damon Gets Political in Passionate MIT Commencement Speech
The ruse is legitimately funny, but behind it is a belief in service that to Damon is no laughing matter.
Earlier this month, the actor gave a commencement address to graduating students from the Massachusetts Institute of Technology, where he discussed Water.org, and implored the young adults to utilize their education to try and address problems they see in the world head-on.
WATCH: Matt Damon Pops Out of Ben Affleck's Coat, Crashes Jimmy Kimmel's Post-Oscars Special
"MIT, you have to go out and do really interesting things, important things, inventive things, because this world has some problems that we need you to drop everything and solve," he said.
"There's a lot of trouble out there, MIT, but there's a lot of beauty too, and I hope you see both."
Watch the video below for more of his inspiring address.