The answer? According to The Wall Street Journal, Lionsgate, the studio that produces "Mad Men," spent about $250,000 on the deal, making it the most expensive music deal the studio has ever made.
Critics often praise "Mad Men" for its cultural accuracy, and there is perhaps no greater cultural influence of the 1960s than The Beatles. "Mad Men" creator and showrunner Matthew Weiner told The New York Times that he felt the show "lacked a certain authenticity because we never could have an actual master recording of the Beatles performing.”
“Not just someone singing their song or a version of their song, but them, doing a song in the show," Weiner told The Times. "It always felt to me like a flaw. Because they are the band, probably, of the 20th century.”
While covers of Beatles songs are often featured on TV programs, commercials and films -- which only require licensing the publishing rights, not the rights to the master recording -- the band’s own recordings are rarely heard on TV or in films, which makes Lionsgate's deal even more surprising.
The surviving Beatles, along with Yoko Ono and Olivia Harrison, who are all known to be picky licensors, signed off on the “Mad Men” deal.
Take a look at more photos from "Mad Men" Season 5:
RELATED ON HUFFPOST:
HuffPost Entertainment is your one-stop shop for celebrity news, hilarious late-night bits, industry and awards coverage and more — sent right to your inbox six days a week. Learn more