He better get used to it!

Tom Hiddleston arrived in LA this morning and didn't seem to be in the best mood, which could be because co-star Robert Downey Jr. totally burned him on Instagram! Taylor Swift's boyfriend just joined the social media site, and the Iron Man star couldn't resist making a pretty epic joke on his own account about the British hunk's relationship with T-Swizz.

"Join me in welcoming the biggest T. Stark fan of them all to Instagram! @twhiddleston," he captioned the below photo of Hiddleston wearing that infamous "I Heart TS" tank. In case you didn't know, Tony Stark is RDJ's character in the Marvel movie.

We wonder if the "Wildest Dreams" songstress is en route to the City of Angels now that her man is in town? She's currently in NYC, but knowing her, she's probably on the next flight out west!

Join me in welcoming the biggest T. Stark fan of them all to Instagram! @twhiddleston

A photo posted by Robert Downey Jr. (@robertdowneyjr) on