Lady Gaga will be the musical guest and Justin Timberlake will serve as guest host on a powerhouse season finale of 'Saturday Night Live' set to air May 21 on NBC.

Gaga was the musical guest once before on 'SNL' in October 2009, while Justin has already hosted the show three times. His most memorable appearances on the sketch-comedy program include his musical collaborations with 'SNL' castmember Andy Samberg in the digital shorts 'D--- in a Box' and 'Motherlover.'

Look for Gaga to perform at least two songs off her upcoming album, 'Born This Way,' which drops two days later on May 23. Meanwhile, Justin will be promoting his role in the forthcoming film, 'Friends With Benefits,' which is set to hit theaters on July 22.

Watch Justin Timberlake and Andy Samberg in the 'D--- in a Box' Digital Short From 'SNL'

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