TALLAHASSEE, Fla. (AP) — Former Florida Gov. Charlie Crist, who was elected the state's chief executive as a Republican and then ran unsuccessfully for the U.S. Senate as an independent, announced on Twitter that he's switching to the Democratic Party.

The announcement Friday night fanned speculation that Crist would seek to regain his old job from Republican Gov. Rick Scott in 2014.

Crist sent out a tweet that said, "Proud and honored to join the Democratic Party in the home of President (at)Barack Obama!"

The tweet included a photo of a smiling Crist and his wife Carole as he held up a Florida voter registration application. The Tampa Bay Times reports that Crist signed the papers changing his affiliation from independent to Democrat at a Christmas reception at the White House. President Barack Obama greeted the news with a fist bump.

"I've had friends for years tell me, 'You know Charlie, you're a Democrat and you don't know it,' " Crist told the newspaper Friday night.

He cited the Republican Party's shift to the right on a range of issues, including immigration, education and the environment.

Messages left for Crist by The Associated Press weren't immediately returned Friday night.

Crist was elected Florida governor in 2006 while in the GOP. As he moved to run for the U.S. Senate in 2010, he faced a tough primary challenge from the right and bolted the GOP to run as an independent. He lost a three-way Senate contest in 2010 to Republican Marco Rubio.

Crist, 56, spoke at the Democratic National Convention in Charlotte, N.C., that nominated Obama for a second term and campaigned for his re-election.

Crist's decision to switch to a Democrat will increase speculation that he intends to challenge Scott, a former hospital chain CEO who has struggled with low favorability ratings since taking office. Crist has already criticized Scott for refusing to extend early voting despite pleas from U.S. Sen. Bill Nelson and other Democrats.