Fred Thompson Quits 'Law & Order,' Moves Closer to 2008 White House Bid

Actor Fred Thompson quit the TV series "Law & Order" to focus on his likely 2008 run for the White House, FOX News has learned.

The former Tennessee Republican senator told FOX News on Thursday that he plans to focus on raising money and hiring staff.

"It's a daunting challenge, it takes a while to get your team together and get up and running but we're taking the steps necessary to put us there to make that decision," Thompson told FOX News at a stop in McLean, Va.

Thompson plans to form a "testing the waters" committee, "Friends of Fred Thompson," on Friday to begin raising money and hiring staff without officially announcing a White House campaign in July.

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"We'll go into the testing the waters phase and that will allow us to raise some money and start building a staff to get out there and make sure that what we feel like is going on is going on," Thompson said. "There's a desire for someone to come in and run a different kind of campaign and come with a different message and address some of the issues our country is facing."

Dick Wolf, creator and executive producer of "Law & Order"," said Thompson told him he "has not made a firm decision about his political future," but expressed concerns about the show's production schedule.

Thompson said he told the show he wasn't coming back, which shows the "seriousness with which I'm looking to run" for president.

Thompson is likely to announce plans to officially begin a presidential campaign around the July 4 holiday.

Thompson is posturing himself as the more conservative alternative to would-be opponents former New York City Mayor Rudy Giuliani and Arizona Sen. John McCain, and more steadfast than former Massachusetts Gov. Mitt Romney, who is facing criticism for recently switching views on some conservative issues.

FOX News' Carl Cameron and The Associated Press contributed to this report.