Updated

When Shia LaBeouf posted a 12-minute short film online on Monday, it drew plenty of attention — but also suspicion over its resemblance to a graphic comic.

On Tuesday, the actor apologized. “I’m embarrassed that I failed to credit @danielclowes for his original graphic novella Justin M. Damiano, which served as my inspiration,” LaBeouf wrote on Twitter. LaBeouf’s short, also about a film critic, was called “HowardCantour.com,” and sites like Buzzfeed and Wired on Monday posted about the similarities in theme and dialog.

“Copying isn’t particularly creative work. Being inspired by someone else’s idea to produce something new and different IS creative work,” LaBeouf wrote. “In my excitement and naiveté as an amateur filmmaker, I got lost in the creative process and neglected to follow proper accreditation.”

He went on, “I was truly moved by his piece of work & I knew that it would make a poignant & relevant short. I apologize to all who assumed I wrote it. I deeply regret the manner in which these events have unfolded and want @danielclowes to know that I have a great respect for his work. I f—-ed up.”

The short, starring Jim Gaffigan, debuted at the Cannes Film Festival in 2012 last year.