Country music is forever changed by the passing of George Jones. That's the sentiment of the icon's fellow musicians, most of whom idolized the legendary singer, while also calling him friend. "The world may have lost the greatest country singer that ever lived," Merle Haggard posted on Facebook today (April 26). Other reactions range from sadness and loss to appreciation and celebration of the Possum's life.

Carrie Underwood posted the above photo on Twitter, saying, "Happy memory of me and George. You may have left us, but your music and your legacy never will."

Brad Paisley offered this sweet sentiment, "My friend, the greatest singer of all time, has passed. To those who knew him,our lives were full. To those of you who don't: discover him now."

Vince Gill wrote, "There aren't words in our language to describe the depth of his greatness. I'll miss my kind and generous friend."

Alan Jackson released a statement, saying, "Well, heaven better get ready for some great country music. While George was known for his wild and crazy days, I've known him for 25 years as a friend. He had grown into a real good man. Of course, he will always be the greatest singer and interpreter of real country music – there'll never be another. Like the song says, 'You know this old world is full of singers, but just a few are chosen to tear your heart out when they sing. Imagine life without them...Who's gonna fill their shoes.'"

Keith Urban shared a musical tribute to late legend (watch below) as well as this endearing tweet: "If I'm blessed enough to make it there, I look forward to you giving me the grand tour. Rest in peace George Jones!!!!!"

Loretta Lynn said, "It's a sad day for country music and a great loss for those of us who knew him. I was blessed to call George my friend. He was one of the best country singers there ever was. My thoughts and prayers are with his wife, Nancy, and all of his family. It's a sad, sad day."

Barbara Mandrell shares, "I believe if you ask any singer who was the greatest country music singer of all time, they would say 'George Jones'. He was without question and by far the BEST! I first met and worked with him when I was 13 years old; I am so very grateful that he was my friend."

Lady Antebellum's Hillary Scott posted, "Saddened by the passing of George Jones. Sending prayers up for his wife and family. Country Music will never be the same."

Sugarland's Jennifer Nettles tweeted, "I'll never forget the first time I heard the story in "He Stopped Loving Her Today". RIP George Jones. Country Legend. U will be missed."

The Bellamy Brothers shared, "Prayers and Condolences go out to the family of George Jones, one of the greats is gone."

Pistol Annies' Angaleena Presley wrote, "One of my dearest memories: Hanging with Papaw in his flea market fruit stand to the tune of boot legged George Jones tapes. Rest in peace."

Little Big Town shared, "There will never be another George Jones. You are and always will be country music. Rest in peace"

Jason Aldean posted, "So sad to hear abt the passing of George Jones. Country music has lost one of our pioneers & legendary icons. You will never be forgotten."

Neal McCoy tweeted, "We lost a great man today,, but his Music and his Spirit will live forever Go get some Rest now George Jones ... you deserve it."

Tim McGraw simply said, "Gone ...... George Jones .....man he was country music."

Faith Hill elaborated, "We lost one of the best voices God created this morning. Our hearts are saddened to hear that George Jones has passed away ... Our thoughts and prayers are with Nancy and all of the family."

Blake Shelton posted, "Really REALLY bad news. We've lost a country music legend. And I've lost a hero and a friend. Goodbye George Jones..."

Luke Bryan wrote, "George. You will be deeply missed. Thanks for the beautiful memories."

Martina McBride posted, "So sad to hear about George Jones . His voice and music will be with us forever. Thoughts go out to all his family, friends and fans."

Sara Evans shared, "So saddened to hear of George Jones' passing. He was an idol of mine and a true legend! One of the best voices of all time. I will miss him."

Kix Brooks wrote, "Possum, angels got a serious lead singer today - God bless Nancy his loving wife - what a guy - what a voice - that was one hell of a show!"

John Rich tweeted, "Every serious country artist in the past 30 years has some #georgejones dna in their blood and music. My God. We've lost our Elvis."

Dierks Bentley posted, "nancy and @gjpossum had a beautiful marriage and special relationship. love you nancy. long live the possum. gonna miss my buddy. real sad."

Billy Ray Cyrus writes in a statement, "I'm stunned and deeply saddened to learn of the passing of my good friend George Jones. The very definition of a legend. Thoughts and prayers."

Trace Akdins simply wrote, "George Jones was my friend, and I loved him."