Authorities confirmed the cause of death of Daniel Mickelson, who passed away on July 4 at the age of 23. The LA County Medical Examiner revealed Tuesday that the actor and model died due to fentanyl and cocaine toxicity and ruled the manner of death as an accident.

Model Meredith Mickelson, sister of Daniel, was the first to break the news of his passing on July 5. In an Instagram post, she wrote, "My heart is shattered and to write this feels so wrong and I don't even know what to say. Yesterday, I lost my brother, my best friend, and the other half of my heart. There wasn't a person I loved more on this earth."

"There's no words that can do him justice that I could write. To know him was to love him. He was the happiest, brightest, most sunshine human to exist and I'm so happy God chose me to be his sister for his whole amazing life," she continued.

Fans and fellow celebrities left messages of condolences in the post's comments section. One of them was Jordyn Woods, who noted, "Praying for you."

Model Amelia Hamlin also commented on the post, saying, "I love you forever Daniel."

Model and actress Kaia Gerber also wrote a tribute for Daniel on her own Instagram story, sharing a screenshot of herself doing FaceTime with Daniel.

"I remember that time we sat on the couch and spent the whole day coming up with our own secret language that we continued to speak every time we saw each other," she wrote. "I wish we could go back there. I wish we were still talking in sentences that probably annoyed everyone else but made us crack up every time."

Daniel's demise is the latest high-profile death caused by accidental drug overdose involving fentanyl. Authorities have determined that Michael K. Williams, who died earlier this month, also ingested fentanyl-laced heroin and cocaine prior to his death. Other celebrities who died from fentanyl overdose include Prince and Tom Petty.

In 2019, Daniel appeared in the film "The Killer Clown Meets the Candy Man." He also starred in the series "Mani."

Tablets believed to be laced with fentanyl are displayed at the Drug Enforcement Administration's Northeast Regional Laboratory in New York
Lauren Smith-Fields was found unresponsive by a white man she met on the Bumble app. In photo: tablets believed to be laced with fentanyl are displayed at the Drug Enforcement Administration's Northeast Regional Laboratory in New York. AFP / Don Emmert