Yoko Ono, the artist and wife of former Beatles member John Lennon, spoke out in the debate about gun control yesterday by sharing a haunting image online.

She uploaded a photograph of the late music icon's bloodied sunglasses to her official Twitter page on what would have been their 44th wedding anniversary (March 20).

A message accompanied the troubling picture (shown below), which read: "Over 1,057,000 people have been killed by guns in the USA since John Lennon was shot and killed on 8 Dec 1980. The death of a loved one is a hollowing experience. After 33 years our son Sean and I still miss him. Yoko Ono Lennon."

"31,537 people are killed by guns in the USA every year. We are turning this beautiful country into war zone. Together, let's bring back America, the green land of peace."

Ono and Lennon were married in Gibraltar on March 20, 1969 and he was tragically murdered outside their New York apartment in 1980.

Watch Ono's birthday message to Lennon here: