Renowned UK artist David Hockney has donated the biggest painting of his career to Tate Britain in London.
The work, Bigger Trees Near Warter, is 4.6m by 12m (40ft by 15ft) and is made up of a grid of 50 small canvases.
The portrait, of a typical Yorkshire landscape, was first exhibited last year at the Royal Academy. It will be displayed at Tate Britain in 2009.
"We are delighted he has decided to give this exceptional work to Tate," said gallery director Nicholas Serota.
Hockney - who is now based in Los Angeles - painted the piece in the county where he grew up.
The work also has the French name Peinture en Plein Air pour l'age Post-Photographique.
"Standing before David Hockney's Bigger Trees Near Warter, the viewer is overwhelmed by the beauty of the winter trees and the energy of the Yorkshire landscape," said Mr Serota.
He added that Hockney had "deftly joined together" the tradition of painting outdoors with the use of digital technology "on a monumental scale".
It is not clear how much the painting is worth, but Mr Serota has hinted the price tag is "in excess" of Hockney's most famous work, The Splash, which was sold in 2006 for £2.6m.
Tate Britain said the piece was so big that Hockney had not been able to see it all at once, so had used drawings and computers to help to solve the issue.
"My picture is adaptable," the artist explained.
"You can split it in two and show one or both halves, or even a quarter of it, or show the painting with two full-scale reproductions that would almost make a cloister," he said.
He has also presented the gallery with two digital photographic renderings of the painting on paper sheets in the same dimensions as the oil.