Former South Carolina governor Mark Sanford (R) is prepping his political comeback and is planning to announce he will run for the congressional seat of Sen.-designate Tim Scott (R-S.C.), according to a strategist with knowledge of Sanford's plans.

The strategist confirmed an announcement will come soon. The news was first reported by CNN's Peter Hamby.

Former South Carolina governor Mark Sanford (R). (Chip Somodevilla/Getty Images)

Sanford's fast-rising political career was derailed in 2009 after his mysterious absence from public view led to an admission of an affair with a woman from Argentina. He served out his term, but he and his wife divorced and he is now engaged to his mistress.

A special election should allow Sanford a unique opportunity to launch a political comeback.

For one, he's running for the seat he represented for six years in the late 1990s, so he's got strong ties to voters there (though two cycles of redistricting have changed the lines to some degree). And second, the special election primary is likely to feature a crowded field in which anything can happen.

If no candidate gets 50 percent of the vote, the race goes to a primary runoff two weeks later. The seat is considered safe for Republicans in the general election.

But Sanford still has to fight to regain his good name. The most recent polls since he left office show well more than half of South Carolina voters view him unfavorably.

Perhaps most intriguing about Sanford's comeback has been the idea that he could be pitted in the primary against his ex-wife, Jenny Sanford, who has said she is considering a campaign of her own. Jenny Sanford distanced herself from her husband soon after the affair went public and was considered a potential Senate appointee before Scott got the nod.

But the strategist said Sanford would not run against his ex-wife, which suggests Jenny Sanford won't run for the seat.

Other declared or possible candidates include state Sen. Larry Grooms; Paul Thurmond, the son of the late senator Strom Thurmond (R) and a recently elected state senator whom Scott defeated in a 2010 primary runoff; state House Majority Whip Jimmy Merrill; and state Rep. Peter McCoy.

The primary is likely to be held in March, depending on when Scott vacates his House seat.