The 30-year-old singer performed for the first time in more than a year over the weekend at the 2015 Special Olympics World Games in Los Angeles.
The star looked healthier than ever as she took the stage in a gorgeous Alice and Olivia sequined gown to perform her hit song "Fly."
"Honored to have performed my song Fly at the opening ceremony for the Special Olympics tonight," she said on Instagram, along with a photo from the night. "All proceeds go to support the Special Olympics. This was a very beautiful night for me. Congratulations to all the athletes.
"Thank you to everyone who supports the Avril Lavigne Foundation," she added. "It has been a difficult year fighting through Lyme Disease for me and I am so happy to have made it on stage tonight for the first performance in a year. Thank you for having me and please enjoy my song Fly. I wrote this song to encourage people who are facing challenges, to encourage strength and to empower. Xoxo"
While the "Complicated" singer is not done with her treatment, she is doing much better after being bedridden during the early stages of her disease.
"I'm about halfway through my treatment," the Canadian singer revealed. "I'm doing a lot better. Seeing a lot of progress. ... I'm just really grateful to know that, like, I will make [a] 100 percent recovery."
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