Leonardo DiCaprio and Robert Redford will be attending the NRDC‘s gala, as their Southern California office is celebrating its 20th anniversary next week.

Hosted by Julia Louis-Dreyfus, the A-list event goes down April 25 at the Beverly Wilshire on April 25th. The guest list also includes Maroon 5, who will be performing at the event while Rosanna Arquette will DJ the afterparty.

“You can be tough doing bad things, and tough doing good things. NRDC, in my opinion, is tough doing good things,” Redford said in a statement.

DiCaprio called the NRDC, “probably the most effective environmental organization in the world. It is willing to take on major corporations and the government itself to hold them accountable for the environmental policy that’s out there.”

A short film will be featured at the Gala that features both Redford and DiCaprio, that depicts the accomplishments of Natural Resources Defense Council’s Southern California office.