Following their concert at the TD Garden in Boston on Wednesday night during a stop on the band’s DNA World Tour, the two singers hosted an after-party at The Grand nightclub, where they asked one lucky couple to join them on top of the DJ booth.
In video captured of the moment, Carter, 39, first has the couple, named Mike and Kelsea, introduce themselves to the crowd. When Carter asks them how they know each other, Mike drops down on one knee and says, “Kelsea is my only one, and I want to ask her to marry me.”
A shocked Kelsea excitedly answers, “Yes! Of course!”
“So since you said she is your ‘only one,’ I think there’s only one song appropriate for her,” Dorough, 45, then says on the mic. Kelsea, clearly thinking the same thing, can be seen mouthing the title of the band’s 1991 hit, “The One.”
Earlier in the night, Carter and Dorough performed other Backstreet Boys hits like “Everybody” and “I Want It That Way.” They also did a meet and greet with about 70 fans at the Scorpion Bar downstairs from the nightclub.
On Jan. 25, the Backstreet Boys released their ninth studio album, titled DNA. After their 4-month Las Vegas residency, Backstreet Boys: Larger Than Life, came to an end on April 27, they kicked off their current DNA World Tour— their biggest arena trek in 18 years — on May 11.
The Backstreet Boys — which, along with Carter and Dorough, also includes band members Kevin Richardson, Brian Littrell and AJ McLean— previously told PEOPLE that they could not feel more grateful for this new chapter.
“For a group like us to still be here 25 years later is a huge testament to the music and a huge testament to our fans — the most loyal fans in the world — sticking with us the entire time and they continue to push us to strive and be better,” said McLean.