Ron Howard, who played Griffith's son Opie from 1960 to 1968 on The Andy Griffith Show, took to Twitter to pay his respects, writing: "His pursuit of excellence and the joy he took in creating served generations & shaped my life. I'm forever grateful. RIP Andy."
Howard isn't the only star who's going to miss Matlock….
"RIP Andy Griffith," Nathan Followill tweeted. "One of my favorite tv actors of all time. I can hear him whistling the theme song all the way to the pearly gates."
Rob Thomas wrote: "just found out [that] ANDY GRIFFITH passed away. an american treasure. if you can, give a little whistle for him today."
"Heaven gained a talented man today," wrote Hilary Scott. "Mr. Andy Griffith, thanks for giving me amazing memories with my family growing up watching your show!"
"From Team Amy - Go Rest High on that Mountain, Andy Griffith," added Amy Grant.
"Michelle and I were saddened to hear about the passing of Andy Griffith this morning. A performer of extraordinary talent, Andy was beloved by generations of fans and revered by entertainers who followed in his footsteps," President Barack Obama said in a statement. "He brought us characters from Sheriff Andy Taylor to Ben Matlock, and in the process, warmed the hearts of Americans everywhere. Our thoughts and prayers are with Andy's family.
"Few people in this world will ever have more influence on our lives than Andy Griffith. An actor who never looked like he was acting, a moral compass who saved as many souls as most preachers, and an entertainer who put smiles on more faces than almost anyone; this was as successful a life as is pretty much possible," Brad Paisley told E! News in a statement. "Andy Griffith made the world a better place, and I was so proud to call him a friend."
"Staying positive and sharing joy," wrote Andie MacDowell. "Andy Griffith will always be remembered for bringing us all peace and wholesome entertainment."
American Idol winner Phillip Phillips wrote: "Can't believe Andy Griffith passed away today. Loved his show. Prayers go out to the family. Used to watch it all the time with my papa."
Another Idol winner, Scotty McCreery, tweeted: " RIP Andy Griffith. We lost a legend today that provided me and my family some great quality time around the tv filled with some good laughs."
"Farewell to a TV ICON :(" Holly Robinson Peete wrote.
Ralph Macchio wrote: " Take a moment and whistle 'The Andy Griffith Show' theme today - finger snap optional - RIP Andy Griffith."
"RIP Andy Griffith. Sometimes I wish the world was as simple as it used to be in Mayberry," tweeted Frank Caliendo.