Katy Perry helped two fans get engaged during her concert in Brooklyn, New York on Wednesday night (11Oct17).

The 32-year-old singer was performing a gig as part of her Witness: The Tour when she invited two women to join her on the stage. After introducing the ladies, she asked one of them, called Katie, what her biggest wish was.

Katie, clearing nervous, then took the microphone and looked at Becky as she told the audience: "Well, I don't know if all of you've all seen Becky, but she's pretty even without any make-up on... she's perfect!"

As Katie pulled a ring box out of her pocket and dropped down onto one knee, Swish Swish star Katy was seen also falling to her knees on the stage in excitement. Katie then asked Becky, "Will you marry me?"

As Becky struggled to control her giggles, Katy jumped up and shouted: "Say yes, Becky, if you want to get married!"

The crowd then went crazy as Becky then managed to squeeze out a "Yes!"

As the couple celebrated their engagement, Katy decided to grab a selfie, telling the two women: "Shall we do a selfie because, like, you're fiancees?"

The proposal was filmed by a fan in the audience and later shared on Twitter. It also fell on National Coming Out Day in America.

Katy has long been a campaigner for Lesbian, Gay, Bisexual, Trans and Queer (LGBTQ) rights and recently spoke about how she felt welcomed into the community after making a name for herself as a music star.

"These people were nothing like I'd been taught to fear. They were the most free, strong, kind and inclusive people," she said during a speech at the Human Rights Campaign Gala back in March.