Kenan Thompson to Guest Judge America’s Got Talent on Sept. 1

Kenan Thompson Steps In for Simon Cowell as AGT Guest Judge on Sept. 1

There’s a new face coming to the America’s Got Talent judges’ panel — and it’s a very familiar one. NBC has confirmed that Saturday Night Live veteran Kenan Thompson will be guest judging the Quarterfinals Round 3 episode of America’s Got Talent on Sept. 1, filling in for a sidelined Simon Cowell. It’s a booking with serious full-circle energy, because Thompson has been here before.

In a bit of TV symmetry, the SNL comedian first stepped in for Cowell back in 2020, when the AGT creator and executive producer was laid up recovering from the horrific e-bike accident that fractured his back. At that stage, Thompson sat alongside regulars Heidi Klum, Howie Mandel and Sofia Vergara, with host Terry Crews keeping the flow moving across two live quarterfinal episodes. Now, five years on, he’s being handed the seat again for the same stage of the competition — the pressure-packed live quarterfinals where acts either break through or go home.

Why Simon Cowell Is Away

For anyone who’s been watching the current run and wondering where the show’s most recognizable judge went, here’s the update: Cowell is taking time off for back surgery. The procedure is described as routine, but it’s a direct consequence of the serious spinal injury he suffered in his August 2020 e-bike accident. That crash also knocked him out of the 2020 season entirely, forcing a rotating cast of guest judges to fill the chair while he endured a long, difficult rehab and recovery.

This time around, Cowell’s absence is expected to be more temporary. The Quarterfinals Round 3 episode on Sept. 1 is slated to have the full judging desk back in place shortly after, with Cowell presumably returning once he’s recovered. For now, though, Thompson gets the spotlight — and the show is thrilled about it.

A Comedy Legend Takes the Judges’ Table

“A comedy legend is taking over the Judges’ table!” AGT announced on social media when it revealed Thompson’s guest stint. The billing is earned: Thompson has spent more than two decades on Saturday Night Live, making him one of the longest-tenured cast members in the show’s history, and he’s a value to any panel he joins. During his 2020 appearances, he offered the kind of supportive coaching that’s become his signature—encouraging nervous performers to turn their energy into fuel for the stage.

That warmth is exactly the vibe AGT looks for in a guest judge. Reality competition shows live or die on the chemistry of their panels, and Thompson slides into that role comfortably: he’s quick with a joke, genuinely invested in the performers’ stories, and never talks down to the amateur acts that make the show what it is. It’s the same easy charisma that’s made him a fixture on everything from comedy specials to celebrity game show panels.

Two Talent-Search Giants, One Booking

Thompson’s arrival is worth watching for how it bridges two of television’s biggest talent-search franchises. He’s joined a long line of guest judges who’ve kept the AGT desk warm over the years — a tradition that stretches back through Cowell’s earlier absences and includes everyone from pop stars to fellow comedians. When America’s Got Talent needs a polished, dependable warm-up fill-in, it tends to reach for exactly this kind of seasoned entertainer.

There’s also a fun angle in the timing. Thompson is a massive star with roots in sketch comedy, and his crossover appeal makes him a natural fit for a show that increasingly casts musicians, dancers, magicians and variety acts from around the world. Watching him react to a death-defying act or a soul singer’s audition in real time is the kind of TV moment that fans genuinely look forward to—and his love of the competition is infectious.

If you’re not caught up, Britain’s Got Talent and the many international versions of the franchise follow the same high-stakes format, so the stakes on Sept. 1 shouldn’t be a mystery to anyone who’s seen one. Cowell built an empire on this exact formula, and having his signature seat filled by an SNL icon is a nod to just how far the format has come.

The guest-judge role is itself a time-honored tradition in the world of reality competition TV. Shows from The Masked Singer to the broader talent-search genre lean on celebrity fill-ins all the time — both to keep the desk lively during a regular’s absence and to bring a fresh set of eyes to acts the core judges may have grown numb to. Thompson slotting in is squarely in that tradition, and a panel gets a different read on performers when someone brand-new is reacting to them without weeks of accumulated bias.

What to Know Before You Watch the Quarterfinals

For viewers tuning in, the Sept. 1 episode is right in the middle of the live quarterfinal stretch — the point in the season where the competition really sharpens and the audience’s votes start to make or break contestants’ journeys. For many acts, this is the first time they’re performing live in front of millions, and a guest judge’s encouragement can be the difference between a confident showing and a nervous stumble. That’s the role Thompson is walking into, and by all accounts it’s one he relishes.

The guest-judge slot also puts Thompson alongside Howie Mandel and Sofia Vergara at a pivotal moment in the season. According to Deadline, this week’s live quarterly episodes featured Mel B, Mandel and Vergara behind the table; Thompson fills in specifically for Cowell for the Round 3 outing. It’s a compact, high-profile gig that lets him dip into the reality-TV world without a long-term commitment — and fans of his comedy will likely be hoping it’s not the last we see of him on the show.

Bottom Line

Simon Cowell’s temporary seat on America’s Got Talent is in very good hands. Kenan Thompson brings decades of live-performance experience, a warm on-camera personality, and a proven track record with the AGT format from his 2020 run. Whether you’re tuning in for the acts or for the judges, the Quarterfinals Round 3 episode on Sept. 1 is shaping up to be one of the more fun nights of the season. And if you need to catch up on how this whole competition machine works, the archive of past AGT seasons—and the full America’s Got Talent library—is right there whenever you’re ready.