In January 1976 Ray Charles completed the musical portion of a 60-second bicentennial themed commercial for McDonalds. The spot was part of a "Special Black Bicentennial Radio" promotion entitled Soul of a Nation, narrated by Bill Cosby, with free brochures dealing with "the monumental contribution Black Americans have made to our country's overall development", distributed through McDonalds outlets.
In the Los Angeles area the radio campaign was launched on 1580-KDAY, on February 9. The introduction ad reproduced here was published in the Los Angeles Sentinel on February 5.
In the late '80s McDonalds' agency developed a commercial character, nicknamed Mac Daddy (or McDaddy), that bears a strong resemblance to Ray. If he refused to collaborate on this one, I can see why. If they got away without paying him for this, I want to hire their lawyer.
(As a matter of fact, the Bobby Darin estate sued McDonalds for more than 10 million dollar for the resemblance with Bobby's tuxedo and singing style).
YouTube shows a series of variations, from all corners of the world:
The briefing for the singer of this commercial's theme song may also have been to "sound like Ray":
And McDonalds' marketing department in the Philippines doesn't behave much better (see comments on YouTube page):