Republican Fred Thompson took the first formal step toward a widely expected bid for the presidency, establishing a preliminary campaign committee on Friday.

The "testing the waters" committee allows Thompson — a former Tennessee senator and actor best known for his film and television roles, including as a prosecutor on NBC's "Law & Order" — to raise money, hire staff and gauge support without officially committing to a White House bid and without having to publicly disclose donations or expenditures.

The "Friends of Fred Thompson" committee was incorporated in papers filed with the state in Nashville, Tenn.

Thompson, 64, a Southern conservative with a right-leaning Senate record, would shake up an already unsettled race for the GOP nomination led by Rudy Giuliani, John McCain and Mitt Romney. Many conservatives have expressed dissatisfaction with the current field of 10 candidates.

By creating the committee now, Thompson avoids having to report to the Federal Election Commission his fundraising totals, donor identities or expenditures on July 15. That's the filing deadline for the second quarter of the year, and the top-tier GOP candidates, as well as seven underdog contenders, must abide by it.

Thompson's timing could significantly dampen the fundraising ability of his potential GOP rivals during the homestretch of the second quarter financial reporting period. Donors who otherwise would have contributed to other Republicans, instead, may choose to give to Thompson.

Officials close to Thompson say he's more likely than not to formally enter the race, perhaps as early as July, and open headquarters in Nashville and the Washington, D.C., area. However, they caution, he's made no final decision about going forward.

Over the past few weeks, Thompson has begun surrounding himself with advisers who served under Ronald Reagan and George H.W. Bush. Among those also expected to play a role: Mary Matalin, a former adviser in the current Bush administration, and Tim Griffin, an ex-aide at the Republican National Committee who as a U.S. attorney in Arkansas was involved in the controversy over the firings of federal prosecutors.

Although he ranks well in national popularity polls, Thompson would enter the race several months behind Giuliani, McCain and Romney in building a campaign organization, raising money and collecting key endorsements.

Given the disparities, he has indicated he favors a nontraditional campaign and already has had a strong presence on the Internet, raising the possibility that he could eschew a traditional media strategy.