The music world mourns the loss of country music legend Merle Haggard.

Best known for celebrating outlaws, underdogs and having an abiding sense of national pride in such hits as "Okie From Muskogee" and "Sing Me Back Home," Haggard died of pneumonia Wednesday at 79, on his birthday.

Take a look at what the stars had to say about his passing.

The Associated Press contributed to this report.