Watch Justin Bieber Cover Boyz II Men's 'I'll Make Love To You'

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Justin Bieber arrives at 102.7 KIIS FM's Wango Tango held at StubHub Center on May 9, 2015 in Los Angeles, California.  

After recently having "pretty much the best day" of his life, Justin Bieber popped into Jazz Night at the W Hotel in Hollywood to cover a classic R&B jam.

Is This Justin Bieber's 'Best Day of My Life'? Pretty Much

The 21-year-old pop star made an impromptu appearance at the L.A. hotel on Sunday, May 24, and delivered a soulful performance of Boyz II Men's 1994 hit "I'll Make Love to You."

Bieber is currently working on new music and shooting the video for his Skrillex/Diplo collaboration "Where Are U Now."

Watch a clip of "I'll Make Love to You" performance below (via TMZ).