Paulina Rubio reunites with her “little sister”…

The 45-year-old Mexican singer reunited with Demi Lovato in Mexico City over the weekend at Lovato’s concert, where Rubio joined her former co-The X Factor USA judge onstage to sing Cyndi Lauper‘s ’80s anthem “Girls Just Want To Have Fun.”

“Thank you for inviting me. I love you little sister, see you soon,” wrote Rubio on social media.

Rubio and Lovato rocked the Palacio de los Deportes stage, singing their hearts out, dancing and hugging each other.

Lovato is currently in Mexico with her Confident World Tour, where she will perform this week in cities including Guadalajara and Monterrey.