Actor Mark Ruffalo called for a Palestinian holiday in a video message at Macklemore's Dublin benefit show on October 26.
"Keep fighting for a free Palestine and humanity all over the world," Ruffalo said.
"There will be no peace until there is equality. Keep fighting the good fight."
The concert launched Macklemore's "Free Palestine" tour, after he was pulled from Ed Sheeran's US tour due to pro-Palestinian remarks.