Hilary Duff turned Madison Square Garden into a Y2K time capsule when she brought ex-boyfriend Joel Madden and his band Good Charlotte on stage for a duet of their 2002 hit 'The Anthem' during the first of her two sold-out New York City shows.
The unannounced reunion delighted longtime fans who remembered the pair's mid-2000s relationship and underscored how Duff and Madden's friendship has continued long after their romance ended.
