To celebrate the 25th anniversary of United Nations' Convention on the Rights of the Child, UNICEF has teamed up with Yoko Ono and David Guetta to assemble a star cast to cover John Lennon's beloved "Imagine" for what they're calling the #IMAGINE Project. 

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The black and white video shows Katy Perry, Will.i.am, MAGIC!, Adam Lambert, Nicole Scherzinger, Cody Simpson, Idris Elba, Lance Bass and other musicians, as well as actors, athletes and dignitaries singing the song emotionally. 

The participants' individual recordings will be compiled by Guetta to be released as a "world version" of "Imagine" on Jan. 1, 2015. 

Watch it here: