TV Guide says that Stamos will appear in one episode of the show.
Details of his character and storyline have not yet been revealed, though he is expected to star alongside Footloose actress Lori Singer.
Stamos recurs as Dr Carl in Glee and has previously had roles in shows including ER and Full House.
Law & Order: SVU airs on Wednesdays at 10/9c on NBC. The episode featuring Stamos and Singer is currently scheduled for April.