Avril Lavigne is an American pop singer.
In the episode "Amish Guy", Meg introduced Eli to music, but having him listen to her iPod. Eli asked her "Why is this woman screaming at me?", to which Meg replied "It's Avril Lavigne." When Eli asked her who she listens to her, she admitted that she doesn't really like her. She just gets pressured into buying all her music.
In the episode "It's a Trap!" Chris (Luke Skywalker) and Peter (Han Solo) had a back and forth discussion about celebrities. One of the conversation tidbits was about a guy who married Avril Lavigne.
In the episode "An App a Day", Chris mentioned that there were multiple other celebrities who have exposed themselves on the internet. A gigantic list of billions of celebrities appeared on screen. One of which was Avril Lavigne.