Tyler Duckworth, who competed on six seasons of reality show “The Challenge” and also appeared on MTV’s “The Real World: Key West,” has died in North Dakota. He was 44.

His mother, Joni, announced his death on Facebook Thursday, writing, “My son, Tyler, passed away earlier this week. Cause of death has yet to be determined. I will post on Facebook about services as soon as his dad and I figure it out.”

Duckworth first appeared on MTV’s “The Real World: Key West” in 2006 and went on to compete on four seasons of “The Challenge” — “The Duel,” “The Gauntlet III,” “Cutthroat,” “Rivals” — and two of the spinoffs, “All Stars 2” in 2021 and “All Stars 3” in 2022. He won “Cutthroat,” with team members Brad Fiorenza, Dunbar Merrill and Tori Fiorenza, and “Rivals” alongside partner Johnny “Bananas” Devenanzio.

Duckworth made his last public appearance at a “Challenge Mania” fan event in Minneapolis on July 31, and posted about it on his Instagram alongside “Challenge” competitors Rachel Robinson, Fiorenza, Tina Barta, Paul Califiore and Mark Long.

Many cast members have since taken to social media to share their shock and sadness over the passing, including Barta, who competed alongside Duckworth multiple times over the last 20 years.

“It’s hard to find the right words when someone who was part of such a meaningful chapter of your life is suddenly gone,” she captioned a video of the pair together. “We shared an experience that very few people will ever fully understand, and somewhere along the way, it became more than a show or an adventure. It became friendship. It became history. It became family. How blessed am I to be surprised by your visit to Challengemania where I got to hug and kiss you one last time. We didn’t want to leave each other. We never do. I love you.”