Big names from Sophia Bush to Prabal Gurung have joined the protest.

Two popular boutique gyms are under fire after it was reported that their chairman would be hosting a fundraiser for Donald Trump.

On Wednesday afternoon, #BoycottEquinox and #BoycottSoulCycle began trending on Twitter after reports that Stephen Ross, founder and chairman of The Related Companies (which owns both brands), would be putting on a re-election fundraiser for Trump. According to the Washington Post, the fundraiser will take place at Ross's mansion in the Hamptons, and donors will be paying anywhere from $5,600 and $250,000 to attend. Some of the higher-paying donors, the outlet reported, would be able to interact and take photos with Trump.

As the news picked up, customers voiced their disapproval of Ross's fundraiser, with many vowing to cancel their memberships. Among those who spoke out were Chrissy Teigen, Sophia Bush, Prabal Gurung, and Billy Eichner.

Equinox and SoulCycle released a statement, saying they don't have "anything to do with the event later this week and do not support it," emphasizing that Ross is a "passive partner" in the businesses.

"As is consistent with our policies, no company profits are used to fund politicians," the statement read. "We are committed to all our members and the communities we live in. We believe in tolerance and equality, and will always stay true to those values. Mr. Ross is a passive investor and is not involved in the management of either business."

Ross is also owner of the Miami Dolphins, leading the team'swide receiver Kenny Stills to call him out on Twitter.

Ross also developed the Hudson Yards project in New York City, and is an investor in companies such as Momofuku, PureWow, and Resy.