Justin Bieber Spotted With Mystery Woman at Craig David Concert in Hollywood (Exclusive)

The 'Sorry' singer spent his Tuesday night hanging out with an unknown woman during a concert at The Roxy in Hollywood.

Justin Bieber was getting down at Craig David's concert at The Roxy in West Hollywood, California, on Tuesday, where the "Sorry" singer was spotted hanging out with a mystery woman in the VIP section during the show.

An eyewitness tells ET that Bieber, 24, spent most of the night hanging out with an unknown blonde woman. The singer was seen with his arm wrapped around her waist during one song, and she was spotted dancing up on him throughout the show.

During his set, David even took the opportunity to give Bieber a shout out from the stage, before breaking into a performance of his song "16" -- which is a mash-up of his debut single "Fill Me In" from 2000, and Bieber's 2015 track "Where Are U Now."

Toward the end of the night, Bieber hopped on stage and joined David. After the two hugged, Bieber took the mic and showered the singer with praise, telling the screaming crowd that he's "got so much love for him."

"He's an amazing guy and he's an incredible artist," the "Love Yourself" singer shared. "I'm just glad to be here, I had so much fun!"

Hours before his performance at The Roxy, David sat down with ET's Deidre Behar, where he had nothing but love for Bieber.

"I've watched Justin grow into the young man that he is now and it's incredible to see him be able to own it in the way that he is," David, 36, shared. "Because I think a lot of us try to understand how someone could actually be in the spotlight like he's been and be able to hold it together, and come with the music and still keep it relevant and keep it fresh."

David also talked about using the instrumentals from "Where Are U Now" for "16," after Bieber sampled "Fill Me In" for his 2013 single "Recovery."

"So there's been a thing from afar," he added. "But put us in a studio and make it happen."

Bieber's night out at the Roxy comes amid reports that he and on-and-off girlfriend Selena Gomez are taking some time apart so that the "Bad Liar" songstress can focus on her health and her family.

A source told ET last week that Gomez is overwhelmed with the media attention surrounding their high-profile rekindled romance.

"Selena is very delicate; her 'comeback' to the spotlight has been tough -- especially with the interest in her personal life with Justin and her mother," the source said. "She is taking time to herself. This is not the first time she has done this."

Rumors that the couple had called it quits yet again surfaced in early March, right after Bieber's birthday. A source at the time told ET that the two were "still together" and that there are "various reasons" the two often spend time apart, but added, "It's not because they are broken up or taking a break."

ET previously reported that Gomez's friends and family, particularly her mother, Mandy Teefey, struggled with the couple's reunion back in January.

While Bieber's been hanging out at concert venues in Hollywood, Gomez has been enjoying the surf and sun on the beaches of Sydney, Australia.

The songstress sported an orange bikini top with black bottoms while lounging on a luxury yacht with some friends in Sydney Harbor on Monday. Check out the video below to hear more.