(CNN) - It may have been a foregone conclusion, but Stephen Colbert formally endorsed his sister in her bid for Congress Wednesday.
The comedian – who appears on his nightly show as a conservative pundit – joked he was ready to join the "poster committee" for sister Elizabeth Colbert Busch's campaign in South Carolina, pulling out some Elmer's glue and glitter to whip up a sign.
He said his endorsement was prompted by a segment on Wednesday's MSNBC program "Morning Joe," where host Joe Scarborough praised Colbert Busch's rival in the South Carolina House race Mark Sanford.
"This morning was just pure infomercial for his old buddy, Mark Sanford," Colbert said.
Sanford is the former governor of the Palmetto State who admitted to carrying out an extramarital affair in 2009. Before admitting to secretly traveling to Argentina to be with his girlfriend, Sanford explained his prolonged absence from public life by saying he was hiking on the Appalachian Trail.
Colbert took particular exception to co-host Mike Barnicle's assertion that "a lot of people, no matter where they are in the ideological spectrum were struck by your honesty a few years ago."
"Was there any fear of that honesty coming back and playing a perilous role in your political future?" Barnicle asked Sanford in the MSNBC interview.
Colbert joked that question was the equivalent of saying: "When Sanford finally resurfaced, the first thing that everyone thought was 'Man, that guy is being so honest about how much he lied.'"
His sister, by contrast, is "a business woman" and "a job creator," Colbert said. Colbert Busch is an official with Clemson University's wind turbine drive testing facility.
"When raising three children on $14,000 a year, (she) went back to school, built a 20-year career in international trade, and is now leading Mark Sanford in two consecutive polls!" he proclaimed, though the graphic shown on screen was inaccurately labeled "South Carolina Senate Race."
Meanwhile, Sanford is touting an endorsement from Ben Frasier, Colbert Busch's rival in the Democratic primary. He won only 4% of ballots cast – or 682 votes – in March's election.
"I am a Democrat, but a conservative one, and I am supporting Mark because I don't think Elizabeth represents the conservative values of this district," Frasier said in a statement. "I know Mark to be a man of integrity who will represent the District well. I am crossing party lines to make this endorsement because with all due respect to Elizabeth she is just too beholden to the political left to represent the Lowcountry effectively."
CNN's Virginia Nicolaidis contributed to this report.