When fans got a peek a few days ago at tomorrow's Friends reunion, some raised concern about Matthew Perry, who appeared to be slurring his words on camera and appeared distant during an accompanying interview with People.

The actor has battled substance abuse in the past, even once admitting he'd forgotten three years of the hit show, which he shot when he was in the grips of addiction.

However, a source tells U.K.'s The Sun that the actor hasn't relapsed, but instead had just undergone "emergency dental surgery" before the much-delayed special shot last month.

"Matthew turned up to the reunion...and members of his team said that he had an emergency tooth procedure that day," the source tells the paper. "That was said to impact his wellbeing and also how he was feeling."

The unnamed source explained, "He had been in pain from what we understand, which caused the slurred speech," adding, "Obviously no one wants to film after a procedure, but it happened."

"Matthew has told those around him that he is sober, and there is no need to worry," the source tells the paper.

ABC Audio reached out to a rep for the 51-year-old actor but has received no response as of press time.

Friends: The Reunion Special drops Thursday on HBO Max.

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