Tom Hanks, Octavia Spencer, George Clooney and more than 40 other high-profile actors are backing SAG-AFTRA’s five-month-old strike against ad agency Bartle Bogle Hegarty.

In a “We Stand United” ad unveiled Tuesday in Variety, signers of the statement of support included Jennifer Aniston, Alec Baldwin, Rachel Brosnahan, Sterling K. Brown, Steve Carell, Bryan Cranston, Tina Fey, Morgan Freeman, Scarlett Johannson, Regina King, Matthew McConaughey, Elisabeth Moss, Emmy Rossum, JK Simmons, Henry Winkler and Alfre Woodard.

“We stand united with our fellow performers who work in commercials and seek access to fair wages, safe sets, access to healthcare and a meaningful pension,” the statement said. “It’s time for advertisers and agencies like Bartle Bogle Hegarty Inc. to do the right thing. When you make an ad, make it union.”

BBH abandoned its union contract in September, asserting that the agreement is outdated and accusing SAG-AFTRA of being inflexible. SAG-AFTRA told its members not to work for BBH, which has produced commercials for Audi, Absolut, Ikea, Samsung, and Virgin Media, and held more than two dozen protests. A recent rally at the La Brea Tar Pits in Los Angeles drew nearly 1,000 members.

“We are getting this level of support because of the momentum of the campaign against BBH reneging on its contract,” said SAG-AFTRA national executive director David White. “We’ve made certain that the members and their representatives have seen and heard that message and it is resonating. Members are coming together to support the union and each other.”

SAG-AFTRA president Gabrielle Carteris told Variety, “The response that we’ve gotten from our members to the BBH campaign has been excellent. What they’re saying to the company is ‘You don’t get to cherrypick what spots you shoot if you have a contract with us. We fought hard for these rights and you’re not going to take them away.'”

SAG-AFTRA will begin commercials contract negotiations with the advertising industry on Feb. 20 in New York City, six weeks ahead of the March 31 expiration of the current three-year deal. The union’s negotiating committee will be chaired by Carteris and White will serve as chief negotiator.

SAG-AFTRA leaders have hammered out the proposal through a required series of member meetings in recent months. The union, which represents about 160,000 performers, is giving no details on the proposal, asserting that “as a matter of longstanding union practice and has instituted a mutually agreed upon news blackout with the industry.” The contract covers about $1 billion in annual revenues for performers.