The actor, who played Chandler Bing in the beloved sitcom, has struggled with substance abuse issues in the past, and admits he battled memory problems during the late 1990s, the U.K.'s Daily Mirror newspaper reports.

When asked to name his favourite Friends episode, he replies "I don't remember three years of it, so none of those... I was a little out of it at the time... Somewhere between seasons three and six."

Perry's weight fluctuated dramatically over the 10 seasons of Friends, and he's previously blamed his body issues on his cycle of substance abuse and rehab.

"I'm a pretty private person but I was on a TV show that 30million people were watching so people knew," he said. "It was very public what was happening to me."

The actor recently dashed hopes of an eagerly-anticipated reunion with his Friends castmates Jennifer Aniston, Lisa Kudrow, Matt LeBlanc, David Schwimmer and Courteney Cox.

It was announced on 13 January (16) that the cast of the comedy series would be reuniting to pay tribute to director James Burrows during a TV special. However, it was later revealed that Perry would not be attending the reunion in Los Angeles at the end of February (16) as he would be appearing in the play The End of Longing in the U.K.

"Matthew may tape something for the tribute. In other words, this is not the reunion people have been hoping for," his representative wrote in a statement at the time.

However, Perry did revive hopes that a reunion with all six castmates could happen at some point, but they will have to be careful not to ruin the good memories the show has left behind.

"I don't know what the price would be but I think the actors would actually be open to it, I do. I think we would be open to doing something, some kind of TV special. I don't know about a movie," he told host Chris Evans on his Radio 2 show.

"It's kind of tough because we've ended on such a high note that we don't want to ruin it, so we'd want to be really careful. Sometimes when you do a reunion it's terrible, and it sort of ruins the memory of the good show that you've done before.

"We've talked about it a little bit over dinner, we like to get together for dinner and we have a good time together. It's a really good group, there isn't a jerk in the group and that really saved us for 10 years."

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Independent: Matthew Perry 'can't remember three years of Friends' because he was