A letter written by John Lennon to the radio and television host Joe Franklin to endorse Yoko Ono’s music sold for $28,171, flying past its presale estimate of $15,000-20,000. It went under the hammer at the Marvels of Modern Music sale hosted last Thursday by RR Auction in Massachusetts, Art Daily reports.

The two-page handwritten letter is dated December 13, 1971. In it, Lennon makes a passionate case for his wife’s musical talents, writing: “I know you’re a musician at heart! And especially I know you dig jazz. Well, Yoko’s music ain’t quite jazz but to help you get off on it, or understand it, please listen to a track on the Yoko/Ono/Plastic Ono Band, called ‘AOS,’ which was recorded in 1968 (pre Lennon/Beatles!) with Ornette Coleman at Albert Hall London, you could call it free form, anyway Yoko sits in the middle of avant-garde, classic, jazz—and now through me and my music—rock ‘n’ roll!”

According to New York Daily News, Lennon succeeded in getting Franklin’s attention. Last Monday, the TV personality said: “Yoko was on my show nine times. John Lennon was on three times. Yoko was only with him one of those times.” Franklin also said that he thought Lennon’s letter was a stunt to convince Ono “to be confident enough to do it on her own.”

The letter was written on official letterhead from Apple Records, the label started by Beatles in 1968 as a creative outlet for the band members’ music, both as a group and individually.