Mark Hamill kicked off the May the Fourth fun early.

The actor shot a Star Wars: Force for Change campaign video for Omaze, and he made it entertaining for everyone. In the video, which was posted Wednesday, Hamill gave fans the shock of a lifetime. They all thought they were being brought in to read lines for a video celebrating the film franchise's 40th anniversary, but instead they were pranked by Hamill as a way to encourage fans to support The Starlight Foundation and UNICEF.

Hamill interrupted each of the fans as they tried to passionately deliver lines, and their reactions were fantastic. Once they got over the shock, they were absolutely thrilled by his appearance.

To contribute to the campaign, visit omaze.com/starwars between now and May 12 to donate funds and enter to win a variety of awesome Star Wars prizes, including a trip to Los Angeles to attend a pre-screening of the next Star Wars movie and have lunch with Hamill, visits to Skywalker Ranch and the new Han Solo movie set, and a ticket to the "Episode VIII" premiere.

"Star Wars: Episode VIII - The Last Jedi" hits theaters Dec. 15.