Paul McCartney said he began drinking heavily and almost quit music altogether after The Beatles broke up, in an interview due to air this week.
The music icon, now 73, admitted turning to alcohol to cope with the strain of leaving the Fab Four in April 1970, according to extracts of a BBC radio interview released Tuesday.
"I was breaking from my lifelong friends, not knowing whether I was going to continue in music," McCartney said.
"I took to the bevvies (drinks). I took to a wee dram. It was great at first, then suddenly I wasn't having a good time. It wasn't working. I wanted to get back to square one, so I ended up forming Wings."
Wings, which included McCartney's wife Linda, formed in late 1971 and began by playing small unannounced gigs to students.The band eventually enjoyed success, but McCartney acknowledged that some of the criticism levelled in the early years was valid, when his first wife, a novice musician, was still learning how to play the keyboard.
"To be fair we weren't that good. We were terrible. We knew Linda couldn't play but she learned and, looking back on it, I'm really glad we did it," he said.
"I could have just formed a supergroup and rung up Eric Clapton and Jimmy Page and John Bonham, but we graduated from playing universities to town halls, which was quite funny as I'd been at Shea Stadium quite recently."
McCartney, 73, said he was pleased he repaired his strained relationship with Beatles bandmate John Lennon before he was shot dead in 1980.
"I was really grateful that we got it back together before he died. Because it would have been very difficult to deal with if ... well, it was very difficult anyway," he said.
In 1982, McCartney wrote the song Here Today about Lennon.
After playing a section from it, he said: "I was thinking of all the things I never said to him. I'm quite private and don't like to give too much away. Why should people know my innermost thoughts? But a song is the place to put them. In Here Today I say to John, 'I love you'.
"You can put these emotions, these deeper and sometimes awkward truths, in a song."
McCartney said rivalry within The Beatles and their rise to global fame helped him to write some of his best tunes.
"When you're younger, more magical things come to you: being in a band, the competition with John, being kids, suddenly getting famous ... all that lent itself to good work," he said.
"If John came up with a brilliant song, I'd go, 'OK, let's try and be brillianter'."