Kelly Clarkson has thrown down the gauntlet more than once with her amazing covers. Now she’s done it again during a PBS performance with Josh Groban. Groban brought her out as a surprise guest for a cover of the haunting Phantom of the Opera ballad "All I Ask of You." And Kelly, of course, kills it. “She’s one of the most versatile singers that I’ve ever heard,” Groban said introducing Clarkson. “She’s got the most beautiful voice that I’ve wanted to sing with for ages.” The pair have recorded a cover of the song as a duet for Groban’s Stages Broadway musicals cover album. Clarkson goes on to say that Phantom is her first-ever musical and that she had long dreamed of playing the iconic role of Christine. Short of dropping $50 to see Phantom live at the Majestic Theatre, this is as close as you’ll get. Plus, this way you can watch it again.