Robert Downey Jr. joins Twitter

The Iron Man has joined the Twitter age.

Yes, Robert Downey Jr. has "finally" — to quote a few of his 300,000 and obviously quickly counting followers — signed up with @RobertDowneyJr.

His accompanying (and characteristically droll) identifier? "You know who I am." His first tweet? "Talk to me, Twitter," alongside a snap of the actor in dark aviators and suit jacket, holding up a sign hand-lettered with "@RobertDowneyJr," in case there was any doubt about his handle.

So far, he's following a couple dozen co-stars, colleagues and compatriots (Gwyneth Paltrow, Jon Favreau, Jimmy Kimmel). And one very lucky bacon food truck in San Francisco.

Favreau rolled out the digital welcome mat: "You wanted him, you got him. Ladies and gentlemen, give a big #FF to @RobertDowneyJr #chef"