It appears the Good Charlotte rocker recently invited the Hollywood actress to his hometown near Annapolis, Md.
E! News can confirm the twosome even stopped by Kentmorr Restaurant for a friendly meal.
"It was pretty cool," owner Tammy Harper told E! News of their visit on Aug. 10. "You have Cameron Diaz here and it's like a walking amusement park…I'm just trying to let them have a nice quiet dinner, enjoy themselves and the sunset."
The couple savored the restaurant's specialty hard-shell crabs topped with Old Bay.
Harper says Madden knew a lot of people in the restaurant—including Top Chef alum Spike Mendelsohn—because he's from the area.
Last week, the "We Are Done" singer posted several photos from his special visit. "Peace&Quiet #ChuckCounty #greetingsfromSoMD," he shared on his Tumblr with a picture of farmland. "Back Home #SoMd #oldBayOnEverything."
Earlier this summer, Madden visited Diaz's family in Florida over the Fourth of July holiday.
"They flew into Orlando and then drove to Tampa where they met up for a reunion," a source told E! News. "It was a great vacation and they had a blast spending time with Cameron's nieces and nephews."
The couple's five-day trip marked the first time Diaz introduced her summer boyfriend to the family.
Could this most recent trip possibly mean Diaz returned the favor by visiting Madden's fam? Your guess is as good as ours. What we do know is this couple is totally serious.
"They are openly acknowledging to friends that they see a long future together, and yes marriage may be a part of that plan," a source recently told E! News. "It's being discussed, whether seriously, who knows."
—Reporting by Claudia Rosenbaum