Mod Sun Tells Fans at L.A. Show They 'Saved My Life' Amid Avril Lavigne Breakup

The show goes on for Mod Sun.

On Sunday night, the "Flames" singer, 36, triumphantly closed out his God Save the Teen tour with a stop at the Fonda Theatre in Los Angeles, after being plagued with upheaval in his personal life throughout the six-week run. Just two days after he kicked off the tour on Feb. 19, a source confirmed to PEOPLE that he and ex-fiancée Avril Lavigne had called off their engagement.

Speaking to a crowd of more than 1,000, Mod Sun (whose real name is Derek Smith) said his fans "saved my life" after the breakup. Before launching into his song "Battle Scars," he also touched on his three years of sobriety and how much his life had changed over the past six weeks.

Despite the split, Mod Sun went ahead with a performance of "Flames," his 2021 duet with Lavigne. He got visibly emotional as he heard her backing track played over the sound system.

Earlier in the night, Mod Sun told the crowd that he was renaming the God Save the Teen song he wrote for Lavigne, 38, from "Avril's Song" to "Los Angeles Song."

"Probably not a good idea to name the song after the person you're with at the time," he said with a laugh.

He also said his current "anthem" is his 2021 song "Karma," a track he had originally written about ex Tana Mongeau. Despite the song's vitriol-laced lyrics — "I hope you choke on every lie you said to me / I hope you move out of this city suddenly / I hope you get everything you deserve / Karma's a bitch, I heard" — Mongeau and Mod Sun appear to be on good terms, as she was in the crowd singing along and showing her support.

Along with Mongeau, there were plenty of other surprise celebrity appearances throughout the night. Blackbear came out on stage with Mod Sun to perform their 2015 song "Shoot 'Em Down," and Mod Sun FaceTimed close friend Machine Gun Kelly for a virtual duet of their 2020 track "Stay Away."

Other special moments included Mod Sun bringing up two mother-daughter pairs on stage while he sang "Single Mothers" and a couple getting engaged in the crowd.

"L.A. that was such an amazing end to this tour," Mod Sun said on his Instagram Story after the concert. "I'm just so grateful. I love y'all so much ... Time for a new chapter."

Lavigne, meanwhile, has moved on with rapper Tyga. Hours before Mod Sun's L.A. concert, the two were photographed on a bike ride and beach stroll in Malibu.

Lavigne and Tyga were first spotted dining together at Nobu on Feb. 20, sparking news of her split from Mod Sun. The two were later spotted arriving together at Leonardo DiCaprio's party during Paris Fashion Week last month.

Although Tyga, 33, bought an $80,000 diamond necklace for the Love Sux artist and a source told PEOPLE that "they're very into each other," they noted: "They're still not exclusive and just getting to know each other."

"They're taking things very slowly to be on the safe side and really get to know each other before diving into something serious," the insider added. "But they are spending a lot of time together. He's about to get locked in working on new music."