(people.com) - Drew Barrymore and Justin Long have broken up, her rep confirms to PEOPLE. "I can confirm the split with no additional comment," said the spokesperson. Barrymore, 33, and Long, 30, were first linked in August of last year, when they were spotted at the Los Angeles hotspot the Chateau Marmont. By November, the pair - who costar together in He's Just Not That Into You - were getting serious. They spent a PDA-packed holiday in Connecticut, including Thanksgiving with Long's family in his hometown of Fairfield.In the following months, the couple seemed inseparable, partying in Vegas, celebrating Barrymore's birthday with Cameron Diaz in Los Angeles and hiking in Hollywood. In the March issue of Vogue, Barrymore said of the relationship, "My cheeks hurt, I'm so happy." Long, appearing with Barrymore on The Oprah Winfrey Show, described her as "the most compassionate person I've ever met." Barrymore and Long recently celebrated his birthday in Michigan, where they are both currently filming projects.