'American Idol' has not only served as the venue for brand new talents but also as a popular outlet for many famous artists in the industry to launch their albums or give their most important announcements.

Here is a look back at some of the best performances of guest artists during this season of 'American Idol' 2012.

Past 'American Idol' runner up, Lauren Alaina, performed during the Top 13 Week to release her debut album, 'Wildflower.' The single she performed from the album is 'Georgia Peaches' with Mary J. Blige as the mentor of that Top 13 Week.

Demi Lovato performed 'Give Your Heart A Break' during the Top 11 Week along with another star who came from the 'American Idol' stage, Chris Daughtry during the same week's results show. It was in 2011 when his band Daughtry released their third album and he performed 'Outta My Head' on the live show.

Lana Del Ray graced everyone during the Top 10 week with her global hit song, 'Video Games.' Haley Reinhart was back for the results nights of the said week and performed 'Free,' as her newest single.

The Top 9 Week was filled with colours from the 'Starships' performance of Nicki Minaj which came from her recently released album, 'Pink Friday.' Scotty McCreery, last season's 'American Idol,' performed a song from his debut album 'Water Tower Town.'

Other memorable artists who graced this season of AI include The Wanted, Kellie Pickler, James Durbin, Jennifer Hudson, Kris Allen, LMFAO, Stefano Langone, Katy Perry, Coldplay, Carrie Underwood, David Cook, Jennifer Lopez, Adam Lambert, and Lisa Marie Presley.

Above all, during the Finale, the most unforgettable music icons who performed on stage were Chaka Khan, Neil Diamond, Jennifer Holiday, John Fogerty, Reba McEntire, Fantasia-Mantasia, Kristin Chenoweth, Nelly furtado, Jordin Sparks, Gladys Knight, Gloria Gaynor, and Rihanna.

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