When it comes to official rap releases, sample clearances are the proverbial wrench in the works. Which is why 2 Chainz cherished a recent note in which he received the blessings of humorist Tom Lehrer, known for recording song parodies in the 1950s and ’60s.

Lehrer (or as 2 Chainz identified him, “an old white guy”) struck a funny bone with the rapper when he cleared a sample for Chaniz’s forthcoming album in comical fashion. Chainz received the news via email that Lehrer granted him permission to use “The Old Dope Peddler,” a song from his 1960 live album Songs By Tom Lehrer. But the message came with additional instructions.

“Def Jam sent me the email and told me to read the whole email chain,” 2 Chainz told Jenny Boom Boom of Hartford’s WZMX. “The dude who cleared the samples at Def Jam said this is the best effin’ quote letter in 20 years.”

In the letter, Lehrer grants 2 Chainz permission but not before employing the same sharp wit that filled his sarcastic song parodies more than fifty years ago. Chainz, still excited about the note, read from his mobile device.

“His email was, ‘As we say in California, whatever. As sole copyright owner of the song ‘The Old Dope Peddler,’ I grant you MFers permission to sample the song. If you need me to sign something let me know. All I ask is that you send me two copies of the CD the day it comes out.’”

2 Chainz took a break before the kicker.

“He said ‘My regards go out to Mr. Chainz. And may I call him 2?’”

The original record, which you can listen to here, was a parody of “The Old Lamp-Lighter” a song that celebrated the man who “made the night a little brighter.” Lehrer flipped the earnest song on its head by paying homage to the “old dope peddler,” who spread “joy wherever he goes.”

“He gives the kids free samples, because he knows full well,” he sings, “Today’s innocent faces, will be tomorrow’s clientele”

2 Chains revealed his sample-clearance news while he was in Hartford, CT June 11, as the opening act on the Drake-headlined Club Paradise tour. His new album Based On A T.R.U. Story, is due to hit stores August 14. Check out the interview here. –Erik Parker, CBS Local