Robert Downey Jr decided to dress in drag for Sherlock Holmes 2.
In one scene of Sherlock Holmes: A Game Of Shadows, the actor - reprising his role as the famous detective - goes under disguise as a woman, to the horror of sidekick Dr Watson (played by Jude Law).
"Yes, dude looks like a lady. It was actually my idea. I don't know what I was thinking," he told Entertainment Tonight.
"I think it was very upsetting to Watson on his honeymoon trip with his wife and then his pal shows up dressed like his mistress."
Robert, whose wife Susan acted as producer for the sequel, said she wasn't too fussed by his feminine transformation.
"I think at this point that there's nothing I can do that's silly or outrageous enough to warrant her attention," he added.
In Sherlock Holmes: A Game Of Shadows, once again directed by Guy Ritchie, Holmes and Watson reunite to solve a murder and battle the detective's greatest adversary, Professor Moriarty, played by Jared Harris.
They are helped by Holmes' older brother Mycroft (Stephen Fry) and a gypsy fortune teller named Sim (Noomi Rapace).
The action adventure is set for release in December.