The worst-kept secret in Florida politics is now official.

Charlie Crist has formally announced his bid for governor as a Democrat.

The state's governor as a Republican from 2007 to 2011, Crist said the more he watched Gov. Rick Scott govern, the more he wanted to run again for the governor's office.

Crist made the announcement at Albert Whitted Park in downtown St. Petersburg.

"Today, I announce I am running for governor of Florida," Crist said. "And the reason is to put you back in charge."

After short speeches from Rep. Kathy Castor and St. Petersburg mayoral candidate Rick Kriseman, Crist came onto the stage in front of a supportive audience.

Crist announced his bid and also touched on the state of the Florida economy, voting rights, the environment and cutting taxes for middle class families.

"(We have to) take back our state's destiny," Crist said. "To chart a new path, one that's built on a foundation of an economy that's fair for the middle class where hard working Floridians have every opportunity to get ahead."

Crist has been building up to an announcement for months, talking to Democratic groups and campaigning with Democratic candidates. This marks Crist first run at public office since his 2010 Senate bid loss to Marco Rubio.

Appealing to voters is key but this gubernatorial race is turning two former allies into bitter foes. And that could make for a nasty race.

He has already set up a website, and his speeches recently have criticized Republican Gov. Rick Scott.

Scott's political committee has already bought anti-Crist ads to begin airing the day of the announcement and the race is expected to be one of the most expensive, brutal governor's races in the country next year.

At this point, Crist is only facing one challenger in the Democratic primary - former state Senator Nan Rich. But most political observers don't see her gathering enough support to go the distance.