As seen in videos shared to social media, a big screen showed in memoriam images of Aaron during a performance of the boy band's latest single "No Place," which member Kevin Richardson explained "is very special to us because that song is about family."
"Everybody in here, we all grew up together," the singer told the crowd, as Nick stood beside him in tears. "We've been through highs and lows and ups and downs—we thank you for being with the Backstreet family for 29 years, for all the love."
He continued, "Tonight we've got a little bit of heavy hearts. Because we lost one of our family members yesterday. We just wanted to find a moment in our show to recognize him."
Each of the four other band members took turns hugging Nick as fans cheered on in support. Howie Dorough then dedicated their next song to Aaron, who he referred to as the group's "little brother."
One fan, Jon D Barker, shared his account of the concert with E! News, calling the event "very emotional."
"During their last single from DNA, the music video was playing on the top screen," Jon told E! News after the show. "The ending images of the video were the photos Nick had shared on Twitter recently to crowd applause, before the band took some time to talk about Aaron's passing and console Nick. Everyone was crying as you imagine."
Before his performance, Nick, 42, shared a message on Twitter and Instagram in memory of Aaron, saying his "heart has been broken."
"Even though my brother and I have had a complicated relationship, my love for him has never ever faded," he wrote alongside a series of throwback photos of the siblings. "I will miss my brother more than anyone will ever know. I love you Chizz., now you get a chance to finally have some peace you could never find here on earth."
On Nov. 5, Aaron's rep confirmed to E! News that the "Crush On You" singer had died at the age of 34. No cause of death has been revealed.
In one of Aaron's last interviews, the former child star revealed he initially got into show business with the dream of following in Nick's famous footsteps.
"I just wanted to be like my brother," he said on an August episode of the Brett Allan Show. "I wanted to do what he was doing because he would come home with all these stuffed animals. I remember very vividly all of these toys. He would bring back this stuff and have 'Nick' on it. So I wanted to become a singer at the age that I did for stuffed animals. Not money. I wanted my own toys."
He added, "Now I'm thinking about it, that's really why I wanted to do this."