Walmart (WMT), which has long taken flak from labor activists over low wages for its workers, was the target of online criticism from a Hollywood actor on Tuesday.

Two and a Half Men star Ashton Kutcher took to Twitter (TWTR) over a report that an Ohio Walmart store was running a food donation program for its own employees. Kutcher tweeted a message asking Walmart’s profit margin was more important than keeping its worker out of poverty. Walmart quickly tweeted back, noting that the charity drive had been “taken out of context” and that it was “proud” of its workers in Ohio, Salon notes.

That prompted Kutcher to post a tweet wondering if Walmart’s employees would be proud of their employer.

When Walmart tried to steer Kutcher toward a video touting opportunities it offers workers, Kutcher relied by noting that Walmart generated $17 billion in profits last year.

Walmart then issued a series of tweets containing positive statistics about its workforce. Kutcher summed up his criticism, tweeting that “Walmart should be the leaders not the low water mark” when it came to compensating its workers.

The nation’s largest retailer has been the target of a sustained campaign by unions and other labor advocates, who have staged protests and work actions at its stores in a bid to get the company to increase wages.

Shares of Walmart rose modestly in Friday morning trading.