en.wikipedia.org/wiki/List_of_celebrities_appearing_on_Entourage

This page says the season lists are for celebrities "playing themselves." But in "The Script and the Sherpa" (Season 1, Episode 5), Apple TV's episode credits list Val Kilmer as "The Sherpa", not as himself. That means his inclusion in the main "celebrities appearing as themselves" list for this episode is incorrect; he belongs with fictional-character appearances instead.

The article intro says this list covers celebrities who appeared on Entourage playing themselves. But in "The Review" (Season 1, Episode 2), Apple TV's official episode page credits Leighton Meester as "Justine Chapin", not as herself. So this entry is misplaced in the main celebrity-self-appearance list.

This page's season tables are described as lists of celebrities who appeared as themselves. However, for "Date Night" (Season 1, Episode 4), Apple TV's episode credits list Leighton Meester as "Justine Chapin". That is a named fictional role, so this entry does not fit the page's stated criteria for the main list.

According to the page introduction, the main season lists are for celebrities appearing on Entourage as themselves. But in "Amongst Friends" (Season 6, Episode 2), Apple TV's official episode credits list Gal Gadot as "Lisa". The same credits separately list Jamie-Lynn Sigler as "Jamie-Lynn Sigler", showing the difference between a fictional role and a self-appearance. So Gal Gadot's inclusion in the main list is incorrect.

According to the article introduction, the main season lists are supposed to include celebrities who appear playing themselves. But in "My Maserati Does 185" (Season 2, Episode 2), Apple TV's episode credits list Holly Valance as "Leanna", while other real-life cameos in the same episode are explicitly credited as "Himself" and "Herself". That shows Holly Valance was not playing herself here, so this entry is incorrect in the main list.

The page says these entries are celebrities who appeared on Entourage playing themselves. But in "Unlike a Virgin" (Season 5, Episode 2), Apple TV's episode page credits Leighton Meester as "Justine Chapin". The same page separately credits actual self-appearances such as Mark Wahlberg and Tony Bennett by their own names. So Leighton Meester's inclusion in this main list is incorrect for this episode.

The page says the main season tables list celebrities who appeared playing themselves. But in "Gary's Desk" (Season 4, Episode 8), Apple TV credits Yvette Nicole Brown as "Daily Variety Agent", while actual self-appearances in the same episode are credited by the celebrities' own names (for example, Mary J. Blige and Peter Jackson). That means Yvette Nicole Brown was playing a fictional role here, so this entry is incorrect in the main list.