If you’ve watched Ken Burns’ “Country Music” on PBS — and, if you’re a country fan, you have — you’ll know that Marty Stuart was a prominent and eloquent presence in that documentary series.

Stuart, a Nashville star of long-standing, told Rolling Stone magazine that, when he heard Burns was interested in doing a documentary on country music, Stuart immediately wrote Burns a letter. The basic sentiment: “If you do this, consider me and my office ground zero for you and your crew. Whatever you need, the answer is yes.”

Burns knew a fount of knowledge when he heard of one and took Stuart up on his offer. The musician gave the documentarian access to his phone book and his archives, both of which were treasure troves.

Stuart, of course, is just as wonderful a performer as he is documentary source, and he will sing in a sold-out concert Wednesday at the Katharine Hepburn Cultural Arts Center. The show will be taped for the CPTV series “The Kate,” which features concerts at the Hepburn Center that then air around the country.

Marty Stuart, 7:30 p.m. Wednesday, Katharine Hepburn Cultural Arts Center, 300 Main St., Old Saybrook; sold out; (860) 510-0453.