Sources close to the actor recently explained why his speech was slurred.

Last week, the first trailer for the highly-anticipated Friends reunion dropped, and fans of the show are incredibly excited. The special gave viewers a snippet of what to expect, including the emotional first time they see each other. Fans can also expect to see the cast members quizzing each other and recreating iconic moments from the series. On top of that, they'll sit down on the Central Perk couch and talk it out. When the trailer dropped, some viewers noticed that Matthew Perry's speech was a little slurred. Others noticed that he appeared to be particularly emotional at one point in the trailer. Sources close to the star, however, have said that he had to undergo emergency dental work just hours before arriving on set. The dental treatment affected both his mood and his speech at the reunion. https://www.instagram.com/p/CPD80JeryNN/ An insider told The Sun: "Matthew turned up at the reunion and members of his team said he had an emergency tooth procedure that day." They continued: "This was said to impact his wellbeing and also how he was feeling. [Matthew] had been in pain from what we understand, which caused the slurred speech. "Obviously no one wants to film after a procedure, but it happened. The feeling was one of huge sympathy for Matthew, especially in recent days, given how people reacted online." They added: "Matthew has told those around him that he is sober, and there is no need to worry." Friends: The Reunion will air on HBO Max tomorrow night in the US. Irish viewers will be able to watch it on Sky and on the streaming service NOW TV. The special will be available to watch on demand from 8am and at 8pm on Sky One.