A handwritten letter from Paul McCartney inviting an unknown drummer to audition for the Beatles was found folded inside of a book at a Liverpool yard sale, giving some insight into the band’s early days.

The letter was written on Aug. 12, 1960 — just days before McCartney and the Beatles left for a formative two-month gig in Hamburg, Germany. It was also two years before the band split with its first drummer, Pete Best, and replaced him with Ringo Starr, forming the band as we know it today.

The note offers an audition to someone who placed an advertisement in the Liverpool Echo just four days earlier. The ad was unsigned and said: “Drummer–Young–Free.”

In the letter McCartney offered the drummer a try-out, but noted that he must be able to travel almost immediately to Hamburg with the band, where they were said to hone their musical talents in low-rent clubs in the city’s famous red-light district.

“Expenses paid 18 pounds per week (approx) for two months,” McCartney wrote in the letter. “If interested ring Jacaranda club.”

The letter was signed, “Yours sincerely, Paul McCartney of the BEATLES.”

It’s not yet known what became of the unknown drummer — whether he auditioned, or if he just wasn’t able to impress the up-and-coming rockers.

The letter, found by an anonymous Liverpool antique coin collector, is set to be auctioned off next month at Christie’s. The auction house said it is expected to draw more than 7,000 pounds ($11,000) when it’s sold on Nov. 15 alongside other pop memorabilia.