Justin Bieber surprised Ariana Grande's fans once more when he joined her onstage during her April 8 show at the Forum in Los Angeles.

Last month, JB made an appearance during Ari's March 28 concert in Miami — but he awkwardly fumbled some of the lyrics of "Love Me Harder." Did he do better the second time around?

For starters, instead of covering one of Ariana's hits, Justin performed his latest song, Skrillex and Diplo's "Where Are U Now."

"I gave you the key when the door wasn't open, just admit it / See I gave you faith and you doubt and it opened, can't deny it," he sang. "Now I'm all alone and my choice to the open / Tell me he, where are you now that I need you?"

Fans were also treated to Justin's killer dance moves, courtesy of a beat-heavy dance interlude. Judging by the audience's reaction, Justin looked and sounded just as amazing in person as he does in the video of the performance, which you can watch above.

During a separate portion of the show, Ariana took things to a whole other level when she covered Whitney Houston's "I Have Nothing."

"It was my go-to song to sing at a gay bar, a karaoke bar, anywhere," Ariana laughed.

We all know Ariana can sing, but covering a Whitney Houston classic is a huge undertaking. However, the "Break Free" singer proved she was up to the challenge, flawlessly rocking those vocals. Also, she looked so elegant perched on a grand piano. You can watch the performance for yourself in the video below!

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