Happy Birthday, Willie Nelson!

If you haven't already said that to the man who many consider to be the greatest country music artist ever, you still can, and you still should -- he hit the big 80 on April 30.

Legacy Recordings created a digital birthday card at HappyBirthdayWillieNelson.com where the Nelson faithful can submit their own video messages to be featured in a special video montage. Some of the stars who have already posted their messages include Julio Iglesias, Paul Anka, Tom Morello, Sandra Bernhard, John Mayer and Mike Ness.

Check out the latest celebrity greetings at willienelson.com/news/.

One way to celebrate Willie's 80th is by listening to his music. Nelson started performing as a kid growing up in Abbott, Texas, and started recording at a young age -- so he's made tons of music. Some of his best albums are "Yesterday's Wine" (1971), "Shotgun Willie (1973), "Phases and Stages" (1974), "Red Headed Stanger" (1975), "Stardust" (1978), "Honeysuckle Rose" (1980), "Pancho & Lefty" (1983), "Me and Paul" (1985),  "Across the Borderline" (1993) and "Two Men With the Blues" (2008).

It's these and many other studio albums, and a virtually endless slew of famous songs, that got Willie into the Country Music Hall of Fame and the Songwriters Hall of Fame and that earned him a Kennedy Center Honor. He also received a Lifetime Achievement Award from the Country Music Association, the first it ever presented, according to CNN.

With his smooth, often-understated baritone, Nelson possesses one of the most unique and recognizable voices in country music, and in music in general. Believe it or not, his singing style, with it's start-stop phrasing, was once thought to be too out-there for Nashville's traditional sensibilities. 

Besides recording some of the finest country to date, the singer-songwriter/guitarist has also earned a huge following as a busy activist for various key causes. He co-created Farm Aid, the festival that has raised more than $43 million to help farm families -- and that hauled him into another hallowed hall: the Agricultural Hall of Fame. Another of Nelson's creations is BioWillie, which makes fuel out of soy and vegetable oils, CNN notes. Willie has also been rather outspoken about his support for the legalization of marijuana. 

Recently, Nelson raised money for the victims of the West, Texas, fertilizer explosion. The town of West isn't far from Abbott, where he grew up.

On April 28, Nelson played a concert to benefit the West Volunteer Fire Department in the wake of the fertilizer plant explosions that killed at least 13 people, including five volunteer firefighters, and injured more than 200, the Los Angeles Times reported.

"West is just a few miles from my hometown of Abbott,” Nelson said in a statement. “I was born and raised here and it was my backyard growing up. This is my community. These friends and neighbors have always been and are still a part of my life. My heart is praying for the community that we call home."

Once again: Happy Birthday, Willie!