Harry Potter actor Daniel Radcliffe has said he is “heartbroken” after hearing about a spate of suicides among young gay American men.

The straight star has become known as a gay rights advocate, having recently appeared in a television ad to combat homophobia.

In a statement given to MTV News, he said: “Learning about the suicide deaths of Tyler Clementi, Seth Walsh, Asher Walker, Billy Lucas and Justin Aaberg has been heartbreaking for me. These young people were bullied and tormented by people that should have been their friends.

“We have a responsibility to be better to each other, and accept each others’ differences regardless of sexual orientation, gender identity, race, ability, or religion and stand up for someone when they’re bullied.”

He continued: “My deepest sympathies go out to the families and friends of these excellent young people. And to all the young people who are being bullied right now, you are not alone.”

The star also urged friends to look out for the signs of depression.

“When a friend is feeling depressed or says they’re thinking of killing themselves, we must take it seriously and get them help,” he said.

Radcliffe’s statement came after a string of reports of suicides of gay teenagers who had been bullied over their sexuality.

News of the deaths hit the world’s media after 18-year-old New Jersey student Tyler Clementi threw himself off a bridge following the discovery that his roommate had allegedly streamed a sex tape of him on the internet.