"I wish people would stop spreading rumors that Charlize Theron and I are dating," he tweeted during the weekend. "Its starting to make Halle Berry jealous."
"There is nothing romantic going on between them," his publicist told People.com. "He has only met Charlize twice."
Stonestreet won an Emmy Award Sunday night for best supporting actor in a comedy for his work on ABC's "Modern Family."
Theron earned an Oscar for the film "Monster." She was recently seen in the big-screen comedy "Young Adult."