They were even wearing matching outfits! 💜
On April 29, during the first of two shows in Toronto at Massey Hall for her Sour Tour, the 19-year-old singer brought Lavigne out on stage to sing a song with her.
Speaking to the sold-out crowd before revealing the surprise guest, Rodrigo said that the person she was talking about "broke down so many barriers, opened so many doors" for girls like her.
"I can't sing her praises enough," she said.
Then, when Rodrigo dropped that the surprise guest was from Canada, the crowd started to scream.
"I'm so so so lucky because she came here tonight to sing with me," she said.
As Rodrigo told the audience that Lavigne was there to perform, they erupted into loud cheers for the Canadian singer.
When Lavigne came out on stage, Rodrigo jumped up and down and then went over to hug her as the audience screamed.
If that wasn't cute enough, they were even wearing matching outfits with plaid skirts and chunky black lace-up boots!
They performed one of Lavigne's most well-known songs, "Complicated," together which had the crowd singing along.
After the show, Lavigne posted photos and a video of the performance on Instagram and said "it was very sweet" to perform with Rodrigo during the Sour Tour.
She also wished the 19-year-old singer a wonderful rest of her tour and told her to "keep killing it."
Rodrigo shared Lavigne's post on her Instagram story the next day and called the Canadian "an icon."
"Can't believe this happened," she said.
During a stop on the tour in support of her debut album Sour on April 7 in Vancouver, Rodrigo ran into a fan at a restaurant after the concert and took super cute photos with her that look like they were just two BFFs hanging out together!