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Joe Jonas is ready to go solo in more ways than one.

The Jonas Brothers singer, 21, has split from Twilight star Ashley Green, whom he began dating in summer 2010. Reps for both stars tell "We can confirm they both have parted ways and have no further comment." 

Explains one insider close to the pair: "They broke up shortly before her birthday, then got back together."

Indeed, Jonas organized Greene's 24th birthday blowout at West Hollywood's STK on Feb. 18. "He wanted to make sure everything was perfect," another source told Us at the time. "He was really sweet and conscientious."

What a difference a few weeks makes. Explains the first source of the sudden split: "Joe wasn't that into it."

Jonas, whose exes include Demi Lovato, Camilla Belle and Taylor Swift (whom he famously dumped during a brief phone chat), gushes about Greene in the new issue of Details mag.

"She really puts my feelings first. She understands my busy schedule," he said of the sexy star, whom he visited in January on the Baton Rouge, La. set of Breaking Dawn. He even met her parents in Jacksonville, Fla. "Her dad can drink me to shame," he joked. "He's awesome."