Robert Downey Jr. took to social media today to caution fans against falling for scammers posing as him online and looking for cash under the guise of donations.

In his first post on Twitter in several days, the Oscar nominee who is the on-screen personification of Iron Man asked fans to “have each other’s backs” when it came to the “scam artists.”

Likely not wanting to put even more of a spotlight on the situation, the star didn’t provide specific details of where these scams are taking place. Not that The Avengers star is any stranger to online charitable pleas. As recently as June, Downey participated in a campaign with Microsoft and Omaze offering to raise big bucks for charity.

In the past, the Marvel leadman has posted video from the set of Avengers: Infinity War offering visits to those who donate to the Random Act Funding effort. He has also invited fans to doante to join him at the premiere of Spider Man: Homecoming too.

Obviously someone was trying to take advantage of that goodwill but Tony Stark is shutting them down.

Besides more Marvel, Downey has an untitled Doctor Dolittle movie from Universal set to come out on April 12, 2019 and a third Sherlock Holmes pic down the line.