Ono lit up the tower on Videy Island near Reykjavik as a choir sang Lennon‘s 1975 song ’Imagine’, reports BBC News.
She was also accompanied by her son Sean Lennon and George Harrison‘s widow, Olivia.
Starr said: “We’re all here for Johnny‘s birthday and the big light… I love the light.”
The tower is a beam of light radiating from a wishing well, which is engraved with the words “imagine peace” in 24 languages.
It will be lit each year between Lennon‘s birthday, 9 October, and the anniversary of his death on 8 December.
Ono, who designed the monument 40 years ago, said: “I got the idea because I just liked the romantic idea of having a building that just appears, emerges once in a while but sometimes it is not seen.”
“I consider myself very fortunate to see the dream my husband and I dreamt together become reality.”
Ono said she had gathered hundreds of thousands of wishes for world peace at art galleries around the world.
The wishes will be stored in capsules and buried on the island, each topped with a tree.