Matthew Lewis claimed a measure of fame by playing Neville Longbottom in the Harry Potter movies. Now that he’s all grown up, Lewis is exploring new ways to keep in front of the public eye. However, when he posed in his underwear for Attitude magazine, his more risqué stab at celebrity shocked one of his most ardent fans—Harry Potter author J.K. Rowling.

“@Mattdavelewis Not as bad as watching Dan in Equus, but close. Warn me next time, for God’s sake,” Rowling tweeted (referencing Daniel Radcliffe’s performance in the play Equus, where he appears nude).

Lewis, perhaps a bit embarrassed, tweeted his apologies. “Well, this is awkward,” he wrote. “Sorry, Jo.” Rowling then offered her support, but not before saying, “Now go put some clothes on.” (ABC News)