Iron Man is smokin’ a pipe… In what will be his first job since the blockbuster ‘Iron Man,’ Robert Downey Jr. is set to star in ‘Sherlock Holmes,’ the Guy Ritchie helmed drama pic. The movie, which will shoot in the September, takes its cue from a forthcoming comic book that producer Lionel Wigram wrote as a selling tool for a new take on the classic character. The concept sees Holmes as more adventurous and less stuffy than previous screen incarnations and mines more obscure character traits. Joel Silver, Lionel Wigram, Susan Downey and Dan Lin are producing. The film will have to contend with Judd Apatow’s Holmes feature, a comedy starring Sacha Baron Cohen as the sleuth and Will Ferrell as his sidekick Dr. Watson. Downey Jr. next will be seen with Jack Black and Ben Stiller in ‘Tropic Thunder’. EXTRAs: Downey Jr. came onto the project via his wife, Silver Pictures executive vp president Susan Downey. Susan Downey and Joel Silver, who produced Ritchie’s upcoming caper flick ‘RocknRolla,’ were working with Ritchie on his version of ‘Holmes.’ Silver showed him Ritchie’s version of Holmes to the Iron Man, sparking his interest.