Months after it was announced that Ashton Kutcher was joining the show, when the new star stepped on set Friday, all attention was focused on him.
"The taping went really well," the on-set source tells PEOPLE. "No one mentioned Charlie."
But the episode – which will show the funeral of Sheen's character, bowling shirt-sporting Charlie Harper – didn't start on a high note, says the source. "It was a little bit rocky during rehearsal, to film without Charlie. He was such a big part of the show. The cast and crew miss Charlie, they do. There was a relationship there."
However, the source adds, "They're welcoming Ashton with open arms."
The live audience enjoyed the taping, the source continues, and Kutcher, 33, was professional and friendly with costars Jon Cryer and Angus T. Jones.
R.I.P. Charlie HarperWhen the new season premieres Sept. 19, Sheen's final storyline will be revealed. Sheen, 45, who was famously fired from the CBS sitcom in March during a battle with the show's creator, Chuck Lorre, over his behavior on and off the set, was last seen on the show running off with Rose (played by Melanie Lynskey), Harper's pretty but peculiar neighbor.
Although the cause of death for Harper was originally a mystery, a source on set for the taping reveals that the character's demise has a comedic element, reports TMZ.com.
In the plotline of the episode, Harper marries Rose. The twist: Rose finds him in the shower with another woman.
At the funeral, the source explains, Rose describes his death as an accident that occurred when Harper "slipped" on the subway tracks and was gruesomely killed – a day after she discovered the other woman. The source's description of the incident: a "meat explosion."
And although the series is undergoing "a big change," the on-set source told PEOPLE that "the flavor of the show is the same. It's funny and risqué."
The source adds: "Ashton brings his own character. He's not Charlie – not trying to be Charlie."
Adam Rose / CBS