Republican attorney Curtis Bostic has picked up two high-profile conservative endorsements in as many days, with less than a week to go in South Carolina’s special election GOP runoff.

In the last 24 hours or so, ex-Sen. Rick Santorum and 1950s pop singer Pat Boone announced their support for Bostic in the runoff against former South Carolina Gov. Mark Sanford.

“Today I’m singing the praises of Curtis Bostic,” Boone wrote in a press release from the 60 Plus Association. “As a former U.S. Marine, Curtis Bostic can always be counted on to be faithful to his office. And Curtis Bostic can always be counted on to be faithful to those who place him in office.”

Boone’s use of the word “faithful” is a fairly overt allusion to Sanford’s highly publicized marital infidelity.

Meanwhile, Santorum’s endorsement of Bostic on Monday is yet another example of a possible 2016 presidential contender poking around South Carolina in recent days.

“Curtis’ groundswell finish to a runoff spot signals a win for the strength of his grassroots supporters and his robust conservative values,” Santorum wrote in an email to Bostic supporters.

Sanford responded Wednesday by announcing the support of several officials from Beaufort County, including state Rep. Bill Herbkersman, Beaufort County Councilman Rick Caporale and Hilton Head Island Town Councilman John McCann.

Bostic and Sanford will face off in an April 2 GOP runoff in the special election to replace now-Sen. Tim Scott, a Republican. GOP Gov. Nikki R. Haley appointed Scott in December to replace former Sen. Jim DeMint after his resignation.

The GOP primary winner will likely be the new Congressman in the 1st District, as it is a traditionally Republican seat. But, Democrat Elizabeth Colbert Busch, sister of comedian and late night host Stephen Colbert, is attracting national attention and has ample financial resources to make the race competitive. The general election will take place May 7.