Taylor Swift's squad just got more girl power.
During the 25-year-old singer's concert at PETCO Park in San Diego, California on Saturday, she brought Canadian pop star Avril Lavigne onstage. The two performed the latter's 2002 hit "Complicated."
"We've been texting all week and we finally got to meet today and she's so cool," Swift told the crowd. "She's so sweet, which I love, when I find out that one of my favorite artists is also super amazing as a person."
She later tweeted that it was "incredible sharing the stage with" with Lavigne.
"'Complicated' is such a brilliant pop song and I just love her," Swift said.
"Such a Pleasure to perform 'Complicated' tonight with @taylorswift on her #1989 world tour! She ROCKS," Lavigne said on Instagram.
"@taylorswift ...... She is a Doll," she added. "Thank you Taylor for having me up on stage and thank you San Diego. #Complicated #Grateful"
This marked one of the few performances for Lavigne since she revealed in April that she has been battling Lyme disease for months. In late July, she returned to the stage for the first time since her diagnosis, performing at the opening ceremony of the 2015 Special Olympics World Games in Los Angeles.
During Swift's concert on Saturday, she also performed with OMI. The two sang his hit 2014 single, "Cheerleader."
Other special celebrity guests who have performed with Swift or just appeared onstage with her during her 1989 tour include Selena Gomez, Alanis Morissette, Fifth Harmony, Little Mix, Ellen DeGeneres and Matt LeBlanc.
Swift's concert took place a day before the 2015 MTV VMAs. She is nominated for a whopping 10 awards. (Check out a full list of 2015 MTV VMAs nominees.)