they've all played gay characters.
Actually, if that were sole criteria, the list would have been much longer.
These performers have two things in common :
1) each actor portrayed a gay man with complete emotional *and* physical credibility
2) each actor is 'arguably' straight in their public lives. Privately, I don't think there's a Kinsey 1 (completely straight) among them. Regardless of how they live their lives, I think that they're all somewhere between Kinsey 2 and Kinsey 5 emotionally and sexually.
Films in question :
Rupert Graves (Maurice)
Chris Meloni (Oz)
Billy Campbell (Tales of the City)
Jake Gyllenhaal (Brokeback Mountain)
Javier Bardem (Before Night Falls, Second Skin)
Russell Crowe (The Sum of Us)
Johnny Depp (Before Night Falls)
Phillip Seymour Hoffman (Flawless, Capote)
Gael Garcia Bernal (Bad Education)
Fabrizio Fillippo (Queer As Folk)
Gale Harold (Queer as Folk)
Peter Saarsgard (The Dying Gaul)