Peek Inside Justin Bieber's 'Endearing' Rehearsal for the 2016 Billboard Music Awards

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Justin Bieber is taking his next scheduled appearance very seriously.

The 22-year-old singer will be performing at the T-Mobile Arena in Las Vegas on Sunday for the 2016 Billboard Music Awards, and if his rehearsal is any indication of what he'll be delivering during the show, prepare to be impressed.

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Bieber dressed in a Mortal Kombat T-shirt and distressed denim jeans for his painstaking rehearsal on Saturday. An eyewitness tells ET that Bieber was giving it his all as he rehearsed a few of his songs like "Sorry" and "Company."

"In between takes, he was live-singing and making sure to hit every note," the eyewitness said. "[It was] really endearing to see how much he cares."

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Bieber's choreographer was at rehearsals, too, helping the singer go over the dance moves multiple times. Bieber was apparently "super into" the choreography.

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According to the eyewitness, Bieber will make use of laser lights and smoke machines on stage as co-ed performers dance around him.

When he's not performing, the Canadian pop star will be seated one row in front of Demi Lovato, Laverne Cox and Mila Kunis.

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WATCH: Billboard Music Awards: 4 Major Moments You Won't Want to Miss

As we patiently wait for the BBMAs to kick off Sunday at 8 p.m. ET on ABC, watch the video below to hear more on the major moments you won't want to miss!