06/18/2012 AT 6:00 AM ET
Bieber recently joined Gomez’s stepdad and mom Mandy Teefey at the Right to Laugh event hosted by the Alliance for Children’s Rights at the Avalon in Hollywood. Teefey, a huge supporter of the organization, purchased an entire table to support the cause, and invited her daughter’s boyfriend to accompany her family.
“Selena and Justin sat side-by-side,” a source tells PEOPLE. “They were laughing and smiling the whole evening. They were being very low-key and gracious as to not take away any attention from the cause.”
The group took in comical performances and skits by a troupe of comedians and fellow celebrities, including Martin Short and Patricia Heaton.
– Jessica Wedemeyer