As soon as President Obama vetoed Congress’ Keystone XL pipeline bill today, organizers of those opposed to the pipeline issued a heartfelt thank you. The thank you note, crafted and posted by 350.org, was signed by several top Hollywood stars, filmmakers, musicians, environmental leaders, two members of Congress and affected landowners and tribal leaders.

The signers included Willie Nelson and Neil Young, who gave a free concert for Nebraska and South Dakota landowners concerned about the threat to water supplies from the tar sands pipeline.

Hollywood actors, some just back from the Oscars ceremony, like Mark Ruffalo and Julianne Moore, also signed the“Dear Mr. President” letter.

(See other celebs, environmental and tribal leaders, authors, actors and athletes who signed the letter on the list below.)

The letter also capsulized why so many opposed the 1,700-mile transcontinental pipeline so vociferously, for many years and over multiple protests, at the White House, pipeline construction sites and the offices of pipeline backers.