The 82-year-old Oscar nominee, known for "Babe: Pig in the City" and "L.A. Confidential," channeled his role as the crotchety, anti-capitalist brother of a billionaire media mogul for the protest organized by the animal rights group People for the Ethical Treatment of Animals.
Cromwell sat on the Starbucks counter wearing a "Free the Animals" T-shirt and read a statement denouncing the surcharge for vegan milk alternatives.
"When will you stop raking in huge profits while customers, animals and the environment suffer?" he demanded as fellow activists streamed the protest on Facebook.
Cromwell glued his hand to the counter, then later used a knife to scrape it off. Police said there were no arrests.
Starbucks outlets in the United States charge 50 cents to a dollar more for drinks made with plant-based milks.
"Customers can customize any beverage on the menu with a non-dairy milk, including soymilk, coconutmilk, almondmilk, and oatmilk for an additional cost (similar to other beverage customizations such as an additional espresso shot or syrup)," a Starbucks spokesperson said in a statement. "Pricing varies market by market."
The spokesperson said Starbucks respects customers' right to voice their opinions "so long as it does not disrupt our store operations."
Cromwell, nominated for an Academy Award for his role as the farmer in "Babe," is a veteran protester who was charged with trespassing in 2017 for interrupting an orca show at SeaWorld in San Diego.