Simon Cowell knows a star when he sees – or hears – one. From One Direction to Carrie Underwood and from The X Factor to American Idol, he’s helped bring former nobodies to house hold names.

In honor of The X Factor premiering tonight, we’ve gathered some of our favorite talents that Simon helped discover!

One Direction

From: Finished third on the seventh season of UK's The X-Factor.

Success: Well, basically they've become the world's favorite boy band, selling millions of records and performings for thousands of screaming girls.

Carrie Underwood

From: The season four winner of American Idol.

Success: Carrie's often been dubbed the Queen of Idol. She's sold over 25 million singles and 15 million albums worldwide. Yeah, she's kind of a big deal.

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Kelly Clarkson

From: Season one winner of American Idol.

Success: She started it all for Idol! She's sold over 23 million albums and 36 million singles worldwide, making her the most successful contestant that's come from the show.

Leona Lewis

From: Winner of UK's The X Factor season three.

Success: She's a multi-platinum selling artist and three-time Grammy nominee. Her single Bleeding Love has earned her the most success and her single I See You for Avatar was nominated for an Oscar.

Susan Boyle

From: Came in second in 2009's Britain's Got Talent.

Success: Talk about the underdog! Nobody expected the voice that she had when she sang her audition song I Dreamed a Dream from Les Miserables. Has released three successful albums and in 2010 was voted 7th most influential person in the world by Time magazine.

Cher Lloyd

From: Finished fourth on the seventh season of UK's The X Factor. Yes, that's right -- she was on the same season as One Direction!

Success: Her hit single Want U Back is crawling up the charts and has gone platinum in the US. Her other single Swagger Jagger is number one UK Singles charts.

Olly Murs

From: Runner up on the sixth season of UK's The X Factor.

Success: Was the opening act for One Direction's US Up All Night tour and is the co-host of UK' The Xtra Factor. His single Heart Skips a Beat is #27 on Billboard's Pop Songs chart. His debut US album In Case You Didn't Know is released September 25th.

Chris Rene

From: Finished third on the first season of The X Factor US.

Success: A Hollywire favorite, his singles Young Homie and Trouble have been on everyone's radar. This debut album I'm Right Here will be released on October 2nd.

Who’s your favorite gem that Simon helped discover? Let us know in the comments section below!

Photos Courtesy of Getty Images