Caan will play Scotty Lavin, a talent manager who becomes E's headache this season. Fichtner (Prison Break) takes on the role of slick TV producer Phil Yagoda, who is trying to remake his hit 1990s teen series for Drama. Letscher, who got some confusing screen time opposite Calista Flockhart on Brothers and Sisters this season, plays Dan Coakley, a TV exec who oversees Drama's TV series.
Entourage returns Sunday, July 12 at 10:30 pm/ET.
Catch up with full episodes and clips in our Online Video Guide
Follow TVGuide.com on Twitter for more breaking news and scoop