The iHeartRadio Music Festival took over Las Vegas this weekend with performances from Justin Timberlake , Ke$ha, and Miley Cyrus . The music bash got an extra dose of Hollywood star power on Friday when Kate Hudson  made an appearance on the stage to present another great Kate: Katy Perry . Meanwhile, Kate's fiancé, Matthew Bellamy, also took to the stage to perform with his band, Muse. On Saturday, Miley made an emotional appearance when she started crying onstage  while performing her ballad, "Wrecking Ball." Afterwards, she changed into a barely-there costume to take over the stage again and mingle with presenters Britney Spears  and Khloe and Kourtney Kardashian.
Britney Spears  joked around backstage.
Miley Cyrus  performed in a tiny white ensemble.
Justin Timberlake  performed on Saturday.
Miley Cyrus  met up with Kourtney Kardashian, Khloé Kardashian, and their sisters.
Britney Spears  waved to the crowd.
Kate Hudson  introduced Katy Perry .
Ke$ha performed with male dancers.
Jay McGuiness of The Wanted kept things casual.
The Wanted's Max George wore a red shirt.
Katy Perry  played with a jump rope on stage.
Robin Thicke wore a black suit.
Miley Cyrus  hugged Britney Spears .
Adam Lambert  performed with fun.
Elton John made an appearance.
Justin Timberlake  took over the stage.
Drake kept things casual backstage.
Keith Urban  posed for photos with his guitar.
Diddy  wore a tuxedo.
Cher Lloyd struck a pose backstage.
The Kardashians introduced a musical act.
Kate Hudson  changed into a purple outfit.
The Kardashians worked their stuff on the red carpet.
Miley Cyrus  and Britney Spears  met up backstage.
Katy Perry  worked her stuff on the red carpet.
Ashley Greene  made an appearance.
Kelly Rowland wore sexy black boots.