The full-page ad in the New York Times carried a simple message: "Imagine all the people living life in peace."
The John Lennon lyric, carried in Sunday's paper, was a message from his widow, Yoko Ono, in the wake of the Sept. 11 terrorist attacks on the World Trade Center, her spokesman confirmed.
The eight-word quotation from Lennon's "Imagine" was unaccompanied by any photos or text.
Ono decided not to sign the ad because "she felt it would be more effective if her name wasn't on it," explained spokesman Eliot Mintz.
"This is one of the ways she makes her feelings known," Mintz said. "The message is in the ad."
Ono, 68, also plans to erect a Times Square-area billboard with another message from Lennon's lyrics: "Give peace a chance."
Lennon was murdered by a deranged fan outside his Manhattan apartment building in December 1980.