The Microsoft founder spent Tuesday on the set of "Frasier" at Paramount Studios filming an episode of the prime-time TV show set to air Nov. 13, according to the show's producer.
Gates will appear in a show that commemorates the 200th episode of the NBC sitcom, which stars Kelsey Grammer as Frasier Crane, a neurotic psychiatrist who hosts his own Seattle-based radio show. The episode featuring Gates celebrates Dr. Crane's 2,000th broadcast on the radio. Gates, playing himself, swings by the radio show to congratulate Frasier as a fan.
"When Frasier is doing the broadcast, (Gates) drops by to offer his congratulations," said Peter Casey, executive producer and co-creator of "Frasier."
"Bill comes into the booth, says what a fan he is, and things start going awry. But we don't want to give all the plot points away."
Microsoft could not be immediately reached for comment.
Gates' TV appearance comes three weeks after the launch of Microsoft's highly touted new operating system, Windows XP, which is scheduled for release this Thursday.
The sitcom's creators hit on the idea of using Gates as a potential guest star a few weeks ago because he was known to be a "Frasier" fan and is friends with Wil Shriner, one of the show's directors.
Casey said Shriner asked Gates to appear on the show. "I'm sure (Shriner) had his eye on a lot of free software," Casey said, laughing.
Gates showed up on the Paramount set Tuesday, accompanied by an entourage, to record a two- to three-minute scene for the show. Gates had to deliver about two to three pages of dialogue, which he accomplished in three or four takes, according to Casey, who said that was not unusual.
Connoisseurs of Gates' performance in videotaped depositions during the government's antitrust trial two years ago may be unsurprised to learn that Gates didn't immediately take to the camera.
"I will say he was a little rough when we started. But he did a very good job," Casey said. "He had his lines down, which is more than we can say some of the time for Kelsey," Casey joked.
There was one other awkward moment, when Gates appeared on the set wearing a shirt exactly like the one planned for Grammer to wear on the show that day. But Gates apparently didn't mind when the wardrobe lady asked him to change his shirt.
"He's very cordial," Casey said.