A rep for TobyMac confirms to ET that McKeehan died of an accidental overdose of fentanyl and amphetamines.
McKeehan died on Oct. 23, after paramedics responded to a cardiac arrest call at the family’s Tennessee home, the Davidson County Medical Examiner’s office confirmed to People. He was 21.
When news of his son's death first broke, TobyMac paid tribute to his memory in a tribute he shared to Instagram.
"He was a magnetic son and brother and friend. If you met him, you knew him, you remembered him," he said. "His smile, his laugh, the encouragement he offered with words or even without. He had an untamable grand personality and dreams to match. And he hated being put in a box."
"He expressed himself through the music he made. And by made I mean, written, recorded, produced, mixed and designed the art. All of it. A true artist," he continued. "His first show was a week ago, and it was nothing short of electric. Everyone felt it, everyone knew it. He could've easily taken the easy route and put music out when he was 12, 14, 16, even 18, but he always said he wanted to live some life and have something to say before he did it. He didn’t want to be a child star, he wanted to be a man with scars and a story to tell. I always admired, respected and encouraged that stand."
Following in the footsteps of his father, McKeehan was an aspiring rapper. Prior to his death, he had released a number of songs and videos on YouTube and social media under the names TRU, Shiloh and Truett Foster.
Shortly before his death, Truett performed his very first show at the Factory in Franklin, Tennessee.
Earlier this month, TobyMac released a song paying tribute to his son, titled "21 Years."
"'21 years' is a song I wrote about the recent passing of my firstborn son, Truett Foster McKeehan. I loved him with all my heart," the artist wrote in a post on Instagram on Jan. 10.
"Until something in life hits you this hard, you never know how you will handle it. I am thankful that I have been surrounded by love, starting with God’s and extending to community near and far that have walked with us and carried us everyday."