Season 1, Episode 4 — "iLike Jake"

Butler was already known for Hannah Montana and Ned’s Declassified Survival Guide when he guest-starred on iCarly’s first season. He played middle school hottie/terrible singer Jake, whom Carly invited on her show to impress him.

Season 1, Episode 11 — "iRue the Day"

After Carly’s brother Spencer saved Plain White T’s singer Tom Higgenson from getting impaled by a falling mall sign, Spencer asked the band to perform on Carly’s show.

Season 2, Episode 9 — "iRocked the Vote"

The American Idol runner-up appeared on iCarly shortly after soaring to popularity on the 2008 season of the singing competition show. On the iCarly episode, Archuleta was a competitor on the fictional America Sings show — and he won! Some poetic justice.

Season 2, Episode 10 — "iMeet Fred"

Lucas Cruikshank’s popular YouTube alter ego Fred stopped by iCarly in Season 2. The plot revolves around Freddie stating that the “Fred” videos aren’t funny — and losing Carly’s show a ton of fans in the process.

Season 2, Episode 20 — "iFight Shelby Marx"

A year before Victorious premiered, Victoria Justice guested on iCarly as a character named Shelby, who agrees to fight Carly for her show.

Season 3, Episode 3 — "iSpeed Date"

Overstreet hadn’t yet appeared on Glee when appeared on iCarly as Eric, one of the guys who tries to take Carly to a dance.

Season 3, Episode 3 — "iSpeed Date"

Another one of Carly’s potential suitors on the speed dating episode is a young Jordan Fisher in one of his very first acting roles. Now, of course, he’s a Broadway star. Too bad Carly passed him over!

Season 4, Episode 2 — "iSam's Mom"

The unfailingly entertaining Jane Lynch was the perfect choice to play Sam’s over-the-top mom. The production team reportedly offered Lynch the role because her stepdaughter Haden was a huge iCarly fan.

Season 4, Episode 6 — "iStart a Fan War"

Miranda Cosgrove’s School of Rock co-star Jack Black stopped by iCarly in 2010 to play Spencer’s online nemesis from the “World of Warlords” game.

Season 5, Episode 1 — "iLost My Mind"

The Big Bang Theory star took a quick break from his own popular sitcom to play a patient on iCarly who thinks he’s from the future.

Season 5, Episode 9 — "iMeet the First Lady"

The former First Lady has played herself on many TV shows, including Sesame Street, Nashville, and iCarly. When she appeared on the latter, she helped Carly connect with her father who was in the military overseas.

Season 5, Episode 9 — "iMeet the First Lady"

Obama no doubt had many real secret service agents with her on iCarly (including some who had to sweep the studio ahead of her arrival), but one of her fictional agents was played by Saturday Night Live star Taran Killam.

Season 6, Episode 2 — "iGo One Direction"

Carly managed to nab One Direction for her show at the height of their popularity — and even found herself getting close with Harry Styles. Cosgrove recently revealed that Styles was her favorite guest star she got to work with.

Season 6, Episode 7 — "iShock America"

After Jimmy Fallon sees some of Carly’s sketches, he invites the iCarly crew to his show. Tina Fey makes an appearance as well when she hops into Fallon’s video chat. Fey once called the iCarly finale one of “the gold standards” of television finales, so she’s a big fan. “I was moved to tears by the iCarly finale,” she told Entertainment Weekly.

Season 6, Episode 9 — "iFind Spencer Friends"

Emma Stone played an iCarly superfan who totally loses it when she spots Carly IRL.

Season 6, Episode 11 — "iLost My Head in Vegas"

The Pawn Stars cast played themselves in this episode. To bail Sam’s mom out of jail, the iCarly crew decided to pawn some of their beloved items — only Chumlee accidentally ate Carly’s prized potato chip.