Saturday Night Live has celebrated its 40th anniversary with a three-hour special featuring guests like Jack Nicholson and Robert De Niro.

Jimmy Fallon and Justin Timberlake kicked off the anniversary show with a medley of music, catchphrases and characters.

Steve Martin, Taylor Swift, Tom Hanks, Paul McCartney, Melissa McCarthy and Keith Richards also joined the party.

Paul McCartney performed an impromptu duet of I’ve Just Seen A Face with Paul Simon.

Other musical guests included Kanye West and Miley Cyrus.

“Tonight is like an enormous high school reunion,” 15-time host Steve Martin said as the show began.

SNL has become a TV institution and numerous cast members – including Dan Aykroyd, Chevy Chase, Eddie Murphy, Amy Poehler, Adam Sandler and Kristen Wiig – have gone on to carve out Hollywood careers.

Creator Lorne Michaels is widely regarded as one of the most revered producers in the business.

“If Lorne didn’t have good taste, this would have gone away a long time ago,” said Mike Myers, whose Wayne’s World skit with Dana Carvey – which he reprised on Sunday – inspired the 1990s comedy film of the same name.

Robert De Niro proclaimed that SNL is “still at it”, adding: “Forty years! That’s like back when TV was still watched on TV.”

A montage of audition tapes, including disappointing ones from Jim Carrey and Stephen Colbert, were also shown.

A spoof news team made up of Tina Fey, Amy Poehler and Jane Curtin appeared together for the Weekend Update, with the top story being none other than the SNL anniversary.

“Viewers of Saturday Night Live span several generations,” Tina Fey reported.

“From the Baby Boomers to Generation X all the way to whatever you call the little dummies who are live-tweeting this right now instead of watching it.”

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