John Lennon is to appear in a charity TV advert.

The Beatles star – who was shot dead in 1980 – will appear in the US commercial for the One Laptop Per Child initiative, which aims to give the world's poorest children solar-powered computers.

In the advert, Lennon is seen saying: "Imagine every child, no matter where in the world they were, could access a universe of knowledge.

"They would have a chance to learn, to dream, to achieve anything they want. I tried to do it through my music, but now you can do it in a very different way."

The charity used digital technology to record John's part in the advert, which can also be seen on video sharing website YouTube.

Yoko Ono, John's widow, has given her permission for his image to be used.

The One Laptop Per Child Foundation was set up in 2005 and starting making the special laptops – which cost less than $200 – late last year.