The 'Sk8er Boi' singer, who split from husband Deryck Whibley last October, has allegedly been enjoying a "low-key" romance with the 26-year-old star of The Hills.
"They're hooking up but they're keeping it low-key," a source told E Online.
"You can tell they're into each other and both like to have a good time. They're cute together," another insider said.
The pair reportedly recently enjoyed a dinner at Los Angeles restaurant Koi before partying at nearby nightclub Voyeur.
Last month, Lavigne took close friends for a "girls-only" holiday in Las Vegas.