No, your not imagining it. It was a a Leibovitz photo shoot.
From Wiki-
On
December 8,
1980, Leibovitz had a photo shoot with
John Lennon for the
Rolling Stone magazine, promising him he would make the cover of Rolling Stone.
[3] After she had initially tried to get a picture with just Lennon alone (she would recall that, "nobody wanted [Ono] on the cover".
[4]), Lennon insisted that both him and
Yoko Ono be on the cover. Leibovitz then tried to recreate the kissing scene from the
Double Fantasy album cover, a picture that she loved.
[4] "What is interesting is she said she'd take her top off and I said, 'Leave everything on' ... not really preconceiving the picture at all. Then he curled up next to her and it was very, very strong. You couldn't help but feel that she was cold and he looked like he was clinging on to her
[5]... I shot some test Polaroids first and when I showed them to John and Yoko, John said, 'You've captured our relationship exactly. Promise me it'll be on the cover'. I looked him in the eye and we shook on it." She was the last person to professionally photograph
John Lennon - he was shot and killed five hours later.