JUST ADDED: 5 Seconds of Summer will be rocking the stage at this year's iHeartRadio Music Festival Village in Las Vegas! The band sat down with Ryan Seacrest to break the news. Click here to buy your tickets now, before they sell out!
Jimmy Fallon ended his first week hosting the 'Tonight Show' with a bang - by bringing back Justin Timberlake for the 5th installment of their hilarious 'History of Rap' segment. Check out the video:
Earlier in the week, Will Smith joined Jimmy for the 'History of Hip-Hop Damcing.' Watch that video below.