Three months after speaking at the Democratic National Convention (DNC) in Charlotte, South Carolina, Charlie Crist has officially become a Democrat.

Late on Friday, the former Republican governor of Florida who made an unsuccessful 2010 bid for the Senate as an independent tweeted a photo of himself with his wife, Carole, holding a voter registration form.

“@charliecristfl: Proud and honored to join the Democratic Party in the home of President @BarackObama!” he messaged to his more than 11,000 followers.

According to the Tampa Bay Times, Crist signed the form while attending a White House holiday party.

“I've had friends for years tell me, 'You know Charlie, you're a Democrat and you don't know it,” he told the paper.

Crist, who has long denied rumors that he's gay, said his decision was based on the GOP's shift to the right.

“What changed is the leadership of the Republican Party. As I said at the convention, I didn't leave the Republican Party, it left me. Whether the issue was immigration, or education, or you name it – the environment. I feel at home now,” he said.