, 26, and Sean Penn
, 50, have ended their courtship, a source told People.com
The couple made headlines earlier this year when spotted vacationing together in Cabo San Lucas, and also when they were snapped at the White House Correspondents' Dinner in Washington D.C.
The reason for their break up is not known but Scarlett was suspiciously absent from the Cannes Film Festival premiere of Sean's movie 'The Tree of Life,' the website reports.
Scarlett is currently filming 'The Avengers,' set to open May 4, 2012.