NEW YORK (AFP) - Pop star Demi Lovato has caused a sensation among her fans through a sensual, in-concert makeout session with fellow singer Kehlani.

Lovato, the former Disney child TV star turned voice of pop hits such as Sorry Not Sorry, ended her North American tour on Monday evening in Newark sitting on a white on-stage bed.

As topless male dancers in white caps and trousers pranced around her, Lovato leaned forward to sing her track Lonely and Kehlani, her opening act, suddenly plopped behind her and reached over to kiss her on the lips.

With fans cheering, Lovato smiled and hugged the rising R&B star before flipping her over and grinding her hips astride her.

Fan footage of the unexpected romp quickly turned viral, with Lovato's concert trending on social media.

For some viewers, what Lovato described as an "incredible fun sexy crazy night" turned into questions about her sexuality.

To one Twitter user who said Lovato should come out of the closet, the 25-year-old told her 56 million followers: "I like my girls just like I like my honey."

The reply was a winking reference to Honey, one of Kehlani's signature songs in which she touches on her bisexuality.

Kehlani on Instagram said that the dancers encouraged her to come on stage for the kiss but "anyone would be stupid not to jump at the chance."

Lovato, who resumes her tour on April 15 with a Latin American swing starting in Sao Paulo, dated the actor Wilmer Valderrama for six years.

Lovato's moment drew parallels to fellow former child actress turned pop singer Miley Cyrus, who describes herself as pansexual.