CNN

Clinton and Bloomberg appeared at a press conference together in May.

WASHINGTON (CNN) - Former President Bill Clinton praised New York City Mayor Michael Bloomberg Thursday, but he made clear that he's already backing another candidate in the 2008 presidential race.

"He's a smart fella, and suppose he couldn't bear being in the Republican Party - which I thought showed great, good judgment on his part," the former president said during his foundation's announcement of a new initiative to aid developing countries.

"I don't have anything else to say about him running for president. I already have a candidate," he added, referring to his wife, New York Sen. Hillary Clinton. "Whoever runs - the voters will decide on who'll be the best, and I think she'll be the best."

Bloomberg officially dropped his affiliation with the Republican Party earlier this week - a move that fueled speculation he is considering jumping into the presidential race as an independent candidate.

But on Wednesday, Bloomberg dismissed the speculation and joked he would only consider running “if everyone in the world was dead and I was the only one alive."

– CNN's Jamie Crawford and Alexander Mooney