It’s the kind of surprise that could send many Backstreet Boys fans straight into labour, but pregnant Californian Christina managed to keep her cool as AJ McLean crashed her beach date to perform a spontaneous seaside serenade.

To celebrate the release of his new single “Love Song Love,” the 43-year-old singer spread some love by treating a lucky fan and their chosen companion to dinner. Members of the Backstreet Army entered the contest by posting their favourite photos with their partners or friends alongside the hashtag #lovesonglove.

Christina announced she had won the competition on Twitter.

“AJ from the Backstreet Boys is buying my husband and I dinner in honour of his new song. My wave of good luck has commenced,” she captioned a screenshot of the Instagram DM, in which a member of the boy bander’s team announced McLean wanted to “treat you and your partner.”

However, Christina got more than she bargained for when she turned up to Santa Monica, California beach with her husband Dorian.

Ready to enjoy a night off from parenting, the pair arrived to a picturesque set up on the sand, put together by Piece of Peace Picnic Company and featuring pretty plants, candles, and lights.

The romantic date was soon interrupted by photographer Alex Stemplewski, whose portraits of strangers around California have attracted him more than 10 million TikTok followers.

“My name’s Alex and today AJ McLean is going to be singing a song for you – and he’s right behind you,” Stemplewski announced before McLean turned up from behind the couple.

Thrilled, the pair received a private beach concert from McLean and his guitarist Zaya Leavitt while fellow beachgoers looked on.

Singing “Love Song Love”, McLean even treated the two to a performance of the Backstreet Boys smash “I Want It That Way”.

If that’s not enough, Stemplewski did a maternity shoot for the pair, before they enjoyed the Santa Monica sunset.

“We surprised a mom and her husband with a pop-up concert and photoshoot featuring AJ McLean (@aj_mclean) and his new song ‘Love Song Love”’. Happy Mother’s Day!” the social media star captioned a video of the surprise, which he posted on Instagram as the US celebrated Mother’s Day on Sunday.

“They are big fans of AJ and thought they were just being treated to a picnic dinner that day until AJ McLean himself and I surprised them with this pop-up concert!”

Christina later described the dreamy series of events as “the most romantic day of my life.”

“It was one of the best days of my life,” she also tweeted. “Truly a once in a lifetime experience. My face hurts from smiling and laughing so much. It’s been a tough year and I needed the check in my win column.”

“Love Song Love” is from McLean’s forthcoming EP. He stars in the music video alongside models Nahla Wyld and Carmen Carrera, who are both trans. In the video, which was directed by René Elizondo, the trio have a wild time enjoying manicures, dressing up, and dancing around a Hollywood dollhouse.

McLean hopes the video generates awareness and discussion in the fight for equality, particularly amid the struggles for acceptance faced by the transgender community.

“At the beginning of Backstreet’s career, there were transgender, gay, lesbian people around. It never bothered me,” McLean recently told ET Canada. “I don’t get it when people think it’s sacrilegious or disgusting. That’s ignorance and people being scared. It’s like, ‘Do you really have an issue with that gay couple or is it your own sh** you’re uncomfortable with? If you never have to deal with that couple, why do you care?’”

Beach serenades aren’t the only big romantic moves McLean has pulled lately. To mark Mother’s Day, he had chefs come to his California home to whip up a five-course meal for his family.

“Only the best #MothersDay gift for Rochelle,” tweeted McLean, who has also launched a nail polish line, Ava Dean Beauty, named after his eight-year-old daughter Ava Jaymes and four-year-old Lyric Dean. “Our own personal chefs cooked us a five course meal to die for. Thanks to chef Charlie, Stephanie and Alison for making this a Mother’s Day to remember.”

Meanwhile, McLean and his group mates have confirmed that their planned summer concerts in Canada have been rescheduled for July and August 2022. Fans who hold onto their tickets will receive an exclusive NFT.