The programme's biggest stars all came out for the finale, with Kelly Clarkson, Carrie Underwood, Jennifer Hudson, and Jordin Sparks all part of the last-night celebrations.

Current judges Keith Urban, Jennifer Lopez and Harry Connick, Jr. all performed - Urban teamed up with Idol winner Underwood for a cover of Tom Petty and Stevie Nicks' rock ballad Stop Draggin' My Heart Around, Harry sang Wonderful World with a young student from the Ellis Marsalis Center for Music in his native New Orleans, and J.Lo hit the stage to belt out her new song Ain't Your Mama and her hit Let's Get Loud.

There was an odd reunion of sorts for J.Lo backstage - her ex-husband Cris Judd was one of the choreographers/dancers for the show. The singer's current beau, Casper Smart, arrived for the finale with Jennifer.

Meanwhile, Idol favourites like Kimberley Locke, Jordin Sparks, Colton Dixon, Justin Guarini, and Tamyra Gray hit the stage at the Dolby Theatre in Los Angeles for a medley early in the show, which finished with Pia Toscano's pitch-perfect rendition of All By Myself.

The performance prompted her mentor, Lopez, to jump to her feet - J.Lo hired Toscano for her recent Las Vegas shows.

Idols "rockers" Caleb Johnson, Bo Bice, Constantine Maroulis, Chris Daughtry, and James Durbin also put on a show, and stars like Ruben Studdard, Clay Aiken, Katharine MCPhee, Scotty MCCreery, Taylor Hicks, Kellie Pickler, Fantasia Barrino, Latoya London, and Lauren Alaina also appeared on the finale of the programme that kickstarted their careers.

American Idol's first winner Clarkson could not make the finale because she is too close to giving birth to her second child, but she taped a hits medley during a recent appearance episode - and that was shown to honour her part in the talent show's history.

Kelly wrapped up her performance with an emotional a cappella rendition of A Moment Like This, the song she recorded as her first single after winning Idol.

Another highlight came as past winners Phillip Phillips, Lee Dewyze, David Cook, Nick Fradiani, and Kris Allen served up a tribute to David Bowie, performing the late rock icon's Starman, The Jean Genie, and Rebel Rebel, and former judge Simon Cowell made a surprise appearance with his fellow former judges Paula Abdul and Randy Jackson to thank the U.S. audience for "inviting us into your homes".

The finale served as a date night for newlyweds Rupert Murdoch and Jerry Hall, who were spotted in the audience, just before Mississippi native Trent Harmon was crowned the 15th and final Idol winner.