Trevor Potter, Stephen Colbert’s lawyer and a partner at Washington law firm Caplin & Drysdale, made an important cameo Thursday night in the finale of “The Colbert Report” on Comedy Central. He and more than 50 of Colbert’s closest friends assured each other, in song, that they would meet again.

The former Federal Election Commission chairman might have been one of Colbert’s longest-running guests, and one of his most significant. Colbert asked Potter to become his lawyer in 2011 after he appeared on the show to explain the law on forming a political action committee. Potter later participated in segments related to Colbert’s own satirical super PAC, which raised $773,704.83 and helped viewers understand campaign finance better than any other news show.