"Elizabeth Colbert Busch is my friend and my sister. I am endorsing her in the Special Election for South Carolina’s First District," Lewis said in a statement. 

Busch is the sister of "Colbert Report" host comedian Stephen Colbert, who often highlights his South Carolina roots and even appeared in the state during the 2012 Republican primary. Lewis referenced the celebrity Colbert in his endorsement. 

"The Colbert family has always been a strong advocate for all the people of South Carolina," Lewis added. I have visited the First District and know they need a powerful voice in Washington; Elizabeth can be that voice. I know she will be a hard working and dedicated Member of Congress who speaks up and speaks out for the people she serves."

Busch is running in the special election for South Carolina's 1st congressional district, which was previously held by Rep. Tim ScottTimothy (Tim) Eugene ScottTim Scott: Moore 'should find something else to do' Overnight Regulation: Senators unveil bipartisan gun background check bill | FCC rolls back media regs | Family leave credit added to tax bill | Senate confirms banking watchdog Hey, NYT, friendships are built on something deeper than race MORE (R) before Scott was appointed to the seat vacated by Sen. Jim DeMint (R-S.C.). The Democratic primary is on March 19.

Busch said she was humbled by Lewis's endorsement.

"To have the endorsement of someone who is universally recognized for his courage and leadership is humbling," Busch said. "I promise to work tirelessly for the people in the 1st district and justify the confidence that they and Rep. Lewis have placed in me."

Earlier in February, Rep. James Clyburn (D-S.C.) endorsed Colbert Busch.