Country star Miranda Lambert is mourning the death of a childhood friend.

"The House That Built Me" singer took to Twitter to share her grief with fans, revealing she and Mark Adams had been pals since they were nine.

She wrote, "I have lost a friend I've had since 3rd grade today in a tragic accident. When will this pain end. Please pray for peace."

As followers lined up to tweet their condolences and best wishes to the singer, she later responded, "Thanks for the prayers. My friend is Mark Adams. We became friends at 9 years old. He was a great person. He is now in heaven with his dad."

And she had a very special message for her fans: "Please call your friends, especially the ones you haven't talked to In a while or maybe are not on great terms with and tell em u love (them)... It's so hurtful when it's too late to do that."

She wasn't the only one paying tribute to Adams - the motor racing world was also grieving his death.

Lambert's friend was bike racer James Stewart's mechanic - he was killed on Thursday morning while helping a stranded motorist in Florida.

The Orlando Sentinel reports an SUV driven by Glen Ross II drifted onto the right shoulder of Interstate 4 and struck Adams, killing him instantly.

Stewart also took to Twitter to share his thoughts, writing in a post, "I'm in disbelief as something so tragic could happen to you while helping someone else in need... I'm stunned because Tex was such a caring & doing for others person. My heart goes out to his family."