The actor said he was speechless to learn of Boss' death at age 40, penning a message on Instagram Dec. 14 accompanied by a throwback selfie. In the photo, the two are wearing matching black snapbacks, reminiscent of the attire they wore while performing together in the 2015 dance movie Magic Mike XXL.
"I have no words," Tatum captioned his post. "There aren't any. My head or heart can not understand this. There is just so much… i don't know where to begin. I love you. I'll see you again my friend. Until then."
The Los Angeles County coroner's office confirmed Boss died by suicide, according to records obtained by E! News.
Boss' wife, Allison Holker, addressed his passing on Dec. 14, saying in a statement that "it is with the heaviest of hearts that I have to share my husband Stephen has left us."
"Stephen lit up every room he stepped into," she continued. "He valued family, friends and community above all else and leading with love and light was everything to him. He was the backbone of our family, the best husband and father, and an inspiration to his fans."
"I'm heartbroken," Ellen said to E! News in a statement. "tWitch was pure love and light. He was my family, and I loved him with all my heart. I will miss him. Please send your love and support to Allison and his beautiful children - Weslie, Maddox, and Zaia."
Read more memories of Boss here.