According to the press release for the episodes of the eighth season of Entourage, Melinda will appear in the episodes 5, 6 and 7 that are set to air on August 21, 28 and September 4 respectively.

Episode #93: “Motherf*cker”
Debut: SUNDAY, AUG. 21 (10:30-11:00 p.m.)
With things not panning out with his new co-star, Drama plots to get Dice back on the show. Eric meets up with Melinda Clarke, Sloan’s ex-stepmother, and the two end up commiserating over their exes. In an effort to repair his image, Vince agrees to a Vanity Fair interview, while Ari has an awkward business meeting with Dana Gordon (Constance Zimmer).

Episode #94: “The Big Bang”
Debut: SUNDAY, AUG. 28 (10:30-11:00 p.m.)
After his interview, Vince tries to make things right with journalist Sophia Lear (Alice Eve). Ari gets a reality check from his lawyer about his divorce. Eric receives an over-the-top gift from Melinda Clarke, and some unsettling news from Johnny Galecki. Turtle meets with his East Coast partners on a new business venture. Drama shows his solidarity.

Episode #95: “Second to Last”:
Debut: SUNDAY, SEPT. 4 (10:30-11:00 p.m.)
Vince continues to woo Sophia. The DeLucas fall in love with a pricey restaurant space, forcing Turtle to pitch his investors for more money. Distraught over Sloan, Eric turns to Melinda (again) and the pair crash Sloanʼs date. Ari makes an emotional connection with the script for Vince and Dramaʼs miner movie.

Source: SpoilerTV