Edgar Ramirez and Darren Criss are the first stars to officially sign onto Ryan Murphy’s “Versace: American Crime Story,” Variety has learned. Alas, Lady Gaga will not be playing Donatella Versace. (But I’ll bet Maya Rudolph — who played her on SNL — is available.) “Versace” will mark the third installment of FX’s “American Crime Story” anthology, following the award-winning “People V. O.J. Simpson” and the upcoming second season that will revolve around the aftermath of Hurricane Katrina. “Versace” will explore the murder of Gianni Versace, who was killed on the steps of his home in Miami Beach by serial murderer Andrew Cunanan, who killed five people that year and then killed himself on a house boat, eight days after killing Versace. Ramirez will play Gianni Versace, and Criss will play Andrew Cunanan.