Former Republican Florida Governor Charlie Crist to speak at upcoming Democratic National Convention

TAMPA (CNN) - Former Republican Gov. Charlie Crist of Florida will speak at the Democratic National Convention in Charlotte, two Democratic officials confirmed to CNN Monday.

The move follows his endorsement of President Barack Obama on Sunday. Crist cited the president's leadership following the economic collapse and surrounding health care, as well as his disagreements with the GOP platform as reasons for his backing.

"The truth is that the party has failed to demonstrate the kind of leadership or seriousness voters deserve," he wrote in the Tampa Bay Times.

After serving at the helm of the Sunshine State, Crist ran unsuccessfully as a Republican and then independent Senate candidate in 2010. He has practiced law in Florida since his Senate loss and switched his party affiliation to no party affiliation.

After the announcement, one Florida State Republican called Crist "the silly putty of Florida politics."

"He'll bend and twist whatever direction you want and if you smash him against the newspaper he'll offer you a poll-tested, mirror vision," Brian Hughes, a well-respected Florida GOP strategist said.

This is not the first time Crist has sustained accusations of playing politics with his party connection. In 2009, while serving as a Republican, he notably hugged the president, a visual used against him during his Senate run. He also touted elements of the stimulus bill signed into law by Obama.