A 30-year-old TV actor and writer is dead and doctors have "no explanation" for the sudden tragedy.

Mike Heslin was known for his role in the TV series Special Ops: Lioness. The San Bernadino, California native suffered an "unexpected cardiac event" according to his partner, recording artist Scotty Dynamo.

“On July 2nd, my husband, best friend, and soulmate @mikeheslin passed away from an unexpected cardiac event after a week long battle in the hospital,” Dynamo wrote in an Instagram post.

TV actor suddenly dies

Heslin appeared as Polo in two episodes of Special Ops: Lioness, created by Yellowstone co-creator Taylor Sheridan.

Lioness paid tribute to Heslin on Instagram, writing, “We are deeply saddened to learn about the passing of Mike Heslin. Our hearts go out to his friends, family and his husband Scott at this difficult time."

Heslin was also known for a role in the Lifetime TV movie The Holiday Proposal Plan. Heslin was also the creator, director, and writer of the 2020 comedy series The Influencers and starred in the show as Taylor.

The actor "was in perfect health" when he died, according to Dynamo.

“Michael was young, in perfect health, and the doctors have no explanation for what happened,” he added.

“He truly was the sweetest, most caring, and loving man on earth, and he brought out the absolute best in everyone who had the pleasure to cross paths with him,” Dynamo wrote.

“Michael, meeting you was the best thing to ever happen to me. You are my world. You are everything to me. When I felt you take your last breath, my heart shattered into a million pieces."

Late actor was an organ donor

Furthermore, Heslin and Dynamo were beginning to start a family before Heslin’s untimely death.

"You would be the world’s most perfect father. If I ever become a dad, I am going to name my son after you and hope that I manage to raise him to become at least half the man you are," Dynamo wrote.

Heslin was also an organ donor, Dynamo added.

“You were the most generous and giving person,” Dynamo added. “It brings me peace to know that, through your wish to be a donor, you have given the gift of life to four different families. I know that you are in a better place and that heaven has gained another angel.”

RIP.