Robert Downey Jr. As Hugh Hefner

Star of Ironman and major Hottie Robert Downey Jr may star as Hugh Hefner in up coming biography called “Playboy”

Hef totally dug Robert in the “Ironman” movie said that he admired his humor and skill in showing his vulnerability.

Chicago is expected to be used for the shooting of scenes focusing on the early years of Playboy magazine. A Chicago native, Hefner grew up in Galewood and launched Playboy here before moving the California.

No word yet on when the cameras actually will begin rolling, but it could happen as soon as next summer — depending on Downey’s “Iron Man 2″ filming and the finalization of the Hefner script.

With “Iron Man” a box-office smash, Downey is very much in demand. A representative for the actor said he’s interested in the Hefner project but is unlikely to commit to it until a script is done and a director is named.

Brett Ratner (”Rush Hour”), announced last year as the “Playboy” director, is no longer attached to the project but may return to it. Brian Grazer is among the film’s producers.