Caleb Willingham, the estranged husband of TLC’s “1000-Lb. Sisters” star Tammy Slaton, has died. He was 40.

Shirley Willingham, his stepmom, confirmed his death to TMZ, but did not share details.

The Post has reached out to TLC for comment.

Caleb, who was known by his nicknames “Killa K” or “Double K,” met Slaton last year at an Ohio rehab center as they underwent treatment for obesity. They wed in November shortly after he popped the question.

At the time, the lovebirds described the day as “magical.”

“Our wedding day was perfect, there was so much love in the room,” Tammy previously told People. “I literally married my best friend.”

But their romance was short-lived — The Sun reported in May that the couple had split.

Sources claimed Slaton was filing for divorce after Caleb gained 30 pounds and refused to stick to his diet in rehab. After tying the knot, Caleb stayed behind while his blushing bride headed to Kentucky.

His loved ones and fans mourned their loss online.

“I can’t believe I’m even making this post, but today GOD called my big brother home,” read one post from a supposed family member, per The Sun.

“R.I.P. Caleb Willingham aka Killla K aka Double K aka one-half of the dynamic WWF tag team champions The W Boys aka my biggest supporter in anything I do,” the relative added. “You will be forever loved and missed. Until we meet again.”

Another wrote, “I still can’t believe it’s real. I’ve been crying all day. I already miss him so much. I know he’s up there rejoicing with your mom and pop, though, and I have to be happy for him for that.”

“Omg,” one fan said. “Prayers to you, Tammy, and all his friends and family.”

“Double K’s credit will always be good in my book. All about the love. I’m sitting here reminiscing about the freestyles in the dorms,” added someone else.

“Rest in eternal peace, Caleb Willingham,” a fan page for the series read. “My sincere condolences to Tammy, your family, and Caleb’s family.”