Doctor Who star Christopher Eccleston is apologizing for bullying a classmate when they were both at school together.

The star got emotional during an interview with Piers Morgan on Good Morning Britain as he recounted his story.

“It was a very sensitive boy in my class. At break time I used to make him give me some of his crops. I did it a few times and I’m very, very ashamed of it,” he said.

Eccleston, 52, said said before he became a bully, he himself was the victim of bullying – and that might have influenced him to act out.

While the actor knows the name of his former bullying victim, he doesn’t know where he is today.

The actor made his revelation as he prepares to work with the Stand Up to Bullying campaign.

“It’s been a great shame,” said Eccleston.