Republican presidential hopeful Fred Thompson on Friday defended his wife's role in his campaign, saying she has only been doing what he had asked her to do.

"If some people who got their feelings hurt anonymously now want to go after her instead of me because they might feel like she's an easier target, there's nothing I can do about that," Thompson said.

"But I don't have any further need for explanation for anything that she's done. Thank goodness she's there," the former Tennessee senator said in an interview on ABC's "Good Morning America."

Thompson's initial efforts to get the GOP presidential nod were plagued by high-profile staff departures and lackluster fundraising. Some critics have blamed the rocky start on the active role played in the campaign by his wife, Jeri, a former political and media consultant.

Thompson explained that his campaign started out "around our kitchen table a few months ago" with "Jeri and me and a couple of friends."

"She is smart and I confide in her," Thompson said. "She helps me in things that I want to do and I asked her to help me do this and be the intermediary."

Thompson said he was busy at the time trying to "disengage" from his obligations as an actor, a radio talk show host and a member of a State Department advisory board.

Thompson, 65, who disclosed in April that he was diagnosed in 2004 with non-Hodgkin's lymphoma, a highly treatable form of cancer, also sought to allay any concerns about his health.

"My latest checkup was 100 percent," Thompson said. "If I thought I had any problems I assure you I wouldn't be doing what I'm doing today. I haven't been sick a day in my life from this. It's a good kind of thing to have if you can say such a thing."