Neil Patrick Harris wants to attract a very specific demographic with “Best Time Ever”: Sarah Silverman, Louis C.K. and their ilk.

On big key to the success of the show — a huge swing for NBC as a live weekly comedy-variety series — is attracting the kind of celebrity guests that will make people tune in. Harris knows that part of his job is creating an atmosphere that is inviting to stars game for the high-wire act of live TV.

“I want (stars like Silverman and C.K.) to think our show is fun and might be fun to play a part in,” he said Thursday during the show’s Television Critics Assn. press tour panel at the Beverly Hilton.

“Best Time Ever” is based on U.K. hit “Ant and Dec’s Saturday Night Takeaway,” which has run on and off for 12 years on ITV. The series is billed as a fast-paced blend of comedy, sketches, gameshow elements, elaborate pranks (via taped segments) and performance opportunities. Harris will give viewers a chance to win cash prizes and to put their friends on the air via hidden cameras, along with all manner of interactive bells and whistles.

In this context, Harris is less a traditional host and more a ringleader. Among the stunts that will be revealed after the show premieres Sept. 15 will be the fact that Harris went undercover to photo-bomb a random wedding.

“My job (as host) is to show you as an audience all these cool things that we’re doing,” Harris said.

Each episode will have a celebrity guest announcer — starting with Reese Witherspoon — and end with a segment dubbed “the end of the show show.” That bit will run four and a half minutes and is described as a big production number, the kind that Harris has become known for through his many awards show hosting gigs, most recently this year’s Oscarcast.

Harris is not only serving as host but effectively as showrunner, with an assist from exec producer Siobhan Greene, who has been with the British series since its inception. She called it “a Rolls Royce of a show with the best driver in history” in Harris. Harris noted that his awards show experience of having to work on the fly, cut and expand material in the moment has been good training.

“Best Time Ever” has an eight-episode order, and Harris said he had a one-year deal as host and producer. Harris said he believed that even if it emerges as a big hit, the show will work better airing in shorter bursts because of the complexity of the production.

“It deserves to be a little bit of an event,” he said.