When former Tennessee senator and actor Fred Thompson makes his presidential bid official Thursday, his Utah supporters are planning to celebrate at a downtown party.

The event is just one of many being organized nationwide by self-described "Fred-Heads" who for months now have been pushing Thompson to get in the race for the GOP presidential nomination.

Thompson is scheduled to formally announce he's running via a webcast Thursday on his campaign site, www.imwithfred.com. Following the announcement, he's expected to campaign in Iowa, New Hampshire, South Carolina, Florida and Tennessee.

"We're just getting started, but I think a groundswell is coming," said Grant Lynn, organizer of the Salt Lake City party, set to begin about 5 p.m. Thursday at the Utah Republican Party headquarters, 117 E. South Temple. Lynn said the party is free and open to the public.

Lynn said he hasn't been involved in politics for years but was drawn back by Thompson.

"I really see that we need to make some changes. It needs to be different than the same ol', same ol'," the Salt Lake City financial planner said. "Otherwise, I'd be a (Mitt) Romney supporter."

Republican Romney, the former leader of the 2002 Winter Olympics in Salt Lake City, is the favored candidate of most Utahns according to recent polls. Like the majority of the state's residents, Romney is a member of The Church of Jesus Christ of Latter-day Saints.

Lynn, who served a mission for the LDS Church in France at the same time Romney did, said he's concerned that national surveys have shown some voters won't support a Mormon candidate for president — no matter what.

"Any observer would have to look at that and say, oh, there's whatever percent who will never vote for Romney," Lynn said, citing polls that put that number at some 30 percent. "That's a lot of people."

Plus, Lynn said, Romney has changed his mind over the years about some key conservative issues including abortion. Romney, who now wants to see abortion banned, ran as a pro-choice candidate for the Senate in 1994 against Sen. Ted Kennedy, D-Mass.

"That has bothered me. That's one of the things I've enjoyed about Fred. He's not compromising," Lynn said, calling him especially tough on national security. "I like his message. I like his approach."

But that isn't likely to last for many Thompson backers, said Kirk Jowers, director of the University of Utah's Hinckley Institute of Politics and a longtime Romney supporter. Thompson "is the proverbial empty vessel," Jowers said.

"Fred is well-known from his TV and movie appearances and certainly has a charismatic, appealing presence," Jowers said, mostly as a result of having "not been scrutinized. Therefore, Republicans can fill him up with all of their beliefs and hopes."