Simon Cowell’s AGT Replacement Revealed: Kenan Thompson Steps In After Back Surgery — Here’s the Full Health Update

If you tuned into the last live episode of America’s Got Talent and found yourself doing a double-take at an empty judge’s chair, you weren’t imagining things. Simon Cowell wasn’t there, and now we know exactly why, who’s filling in, and when he’s expected to be back.

The short version: Cowell is recovering from a back procedure, and AGT has called in a familiar face to hold down the fourth chair while he heals. Here’s everything currently known about the surgery, the recovery timeline, and the guest judge stepping into his shoes.

So Why Is Simon Cowell Missing From AGT Right Now?

Cowell sat out the August 25 live show, and his absence wasn’t a scheduling quirk, it was medical. A representative for the 66-year-old media mogul confirmed he’s undergoing what’s being described as a routine back procedure, and that he’ll likely be away from the show for a few weeks while he heals up.

Host Terry Crews addressed the elephant in the room directly on air, telling viewers the surgery genuinely couldn’t be pushed back, even though nobody should treat it as an emergency situation. He wished Cowell a smooth and speedy recovery, and that sentiment has been echoed across the show’s social channels ever since.

It’s worth saying plainly: this isn’t being framed as a crisis. It’s a planned procedure that simply landed in the middle of AGT‘s live quarterfinal rounds, which means production had to work around it rather than pause for it.

The Back Story: Simon Cowell’s 2020 E-Bike Accident

To understand why Cowell’s back keeps making headlines, you have to rewind to August 2020. That’s when he suffered a serious spinal injury after falling off an electric bike at his home in Malibu, an accident significant enough to require a five-hour surgery involving multiple spinal fusions and a metal rod inserted into his back.

He was candid about the ordeal afterward, telling PEOPLE months later that the first several weeks were genuinely rough before things started improving. The recovery eventually pushed him toward a healthier daily routine built around walking, swimming, and consistent physical therapy. He also revealed later on that the accident left him with lingering nerve damage, a detail that helps explain why back issues have continued to resurface for him years later.

That 2020 injury is the reason this latest procedure isn’t coming completely out of nowhere. It’s widely being reported as connected to that original spinal trauma rather than an unrelated new injury, which tracks with how these things tend to go after major spinal fusion surgery.

Who Is Replacing Simon Cowell on AGT? Meet Kenan Thompson

Here’s the part everyone actually wants to know: AGT announced on Friday, August 28, that Kenan Thompson — the Saturday Night Live mainstay and longest-serving cast member in that show’s history, will slide into Cowell’s seat for the third round of Season 21’s live quarterfinals, airing Tuesday, September 1, at 8 p.m. ET on NBC.

Thompson, 48, will join the rest of the panel, Howie Mandel, Sofía Vergara, and Mel B, for that episode, with the show confirming the news through an Instagram announcement.

And this isn’t Thompson’s first rodeo at that judges’ table. He filled the exact same seat back in August 2020, right after Cowell’s e-bike accident, sitting alongside Mandel, Vergara, and then-judge Heidi Klum for a stretch of live quarterfinals that season. So when producers needed someone who could step in on short notice, keep the energy up, and not try to imitate Cowell’s blunt judging style, Thompson was the obvious call.

Between his Emmy-nominated run on SNL, his stint hosting the Emmy Awards, and years spent working alongside performers of every stripe, Thompson brings a level of comfort to reality-TV judging that few guest stars could match on short notice.

Has Anyone Else Filled In for Simon Cowell Before?

Thompson isn’t the only name associated with covering for Cowell during a health scare. Back during the original 2020 accident, Kelly Clarkson also stepped in for a couple of live shows while Cowell was hospitalized, announcing the news herself on Instagram with a characteristically playful message poking fun at her own qualifications for the job.

That history shows AGT has a pattern of leaning on high-profile friends of the show rather than leaving the panel short-handed, and it’s part of why Thompson’s return feels like such a natural fit rather than a random casting choice.

What This Means for the Rest of AGT Season 21

For now, judges Mandel, Vergara, and Mel B have been carrying the panel without a fourth chair filled during Cowell’s initial absence, and Thompson’s arrival for the September 1 episode fills that gap for at least one night. Whether he’ll stick around for additional episodes while Cowell continues recovering hasn’t been confirmed yet, and NBC hasn’t laid out a firm date for Cowell’s return beyond the general “few weeks” recovery window his team has given.

That timeline puts things on a bit of a collision course with the calendar, though. Season 21’s live finals are scheduled for Tuesday, September 22, with the live finale following on Wednesday, September 23. If Cowell’s recovery runs anywhere close to the outer edge of expectations, fans will be watching closely to see whether he makes it back in time for the season’s biggest moments, or whether Thompson, or another guest judge , ends up sticking around a little longer than one episode.

Simon Cowell’s Health Update: What We Actually Know

To recap what’s been confirmed so far:

• Cowell is undergoing a back procedure connected to his 2020 spinal injury.
• His team and the show have both described it as routine, not an emergency.
• He’s expected to be out for a few weeks.
• He missed the August 25 live show and will miss the September 1 episode as well.
• No official return date has been announced yet.

As more details emerge about Cowell’s recovery and whether he’ll be back at the judges’ table before the season wraps, this is very much a developing story. For now, fans can expect to see Kenan Thompson bringing his signature energy to the panel on September 1, and if the past is any indication, he’ll make it look easy.

America’s Got Talent airs Tuesdays at 8 p.m. ET on NBC, with episodes available to stream the next day on Peacock.