Sunday's one-day strike of 7,000 unionized workers represented by UNITE HERE Local 75, was the third day of walkouts since the festival began Thursday, The Toronto Star reported.
Sheen and his son Emilio Estevez were on the picket line Friday.
Negotiations have been ongoing and unproductive since August, employees say.
Strikers hosted festival-flavored activities with an "alternative red carpet" for passersby to take photos with workers, the Star said.
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