'Remember the Titans' Star Recalls Heroin Addiction In Hayden Panettiere Tribute

"Remember the Titans" actor Ethan Suplee shared a dark moment in his addiction battle while paying tribute to his costar Hayden Panettiere ... recalling the time he smoked heroin at their big movie premiere.

Ethan revealed on Substack that he was high on heroin at the film's 2000 premiere at the Rose Bowl in Pasadena, smoking drugs in a bathroom just moments after sharing a sweet moment with Hayden.

Ethan said Hayden -- who was just 10 at the time -- ran up to him and jumped into his arms.

He recalled ... "Holding her I was lighter, some of her energy and innocence washed over me, and for a moment my smile was genuine."

Ethan then beelined it from the press line to the bathroom ... where he smoked heroin.

He detailed a few other instances throughout the night where he went and smoked in the bathroom.

Ethan said he met the real Louie Lastik -- who he played in the movie -- and he became self-conscious about his weight, so he smoked more heroin and cried while the movie played.

He said seeing Hayden was the only thing that lifted his spirits that night, writing ... "I saw Hayden one last time, as we made our way out of the stadium. Once again, she leapt into my arms, and once again I felt some relief."

Hayden tragically died Sunday after going into cardiac arrest after a possible overdose.

Ethan mourned her loss, as well as another actor and friend, Harold Pruett, who died of an overdose in 2002.

He wrote ... "I feel a tremendous sense of loss today, I don't know what they were going through at the end. I only know that for them, the battle is over. And I'm sad."

The actor said that, while he didn't overdose and die the night he smoked at the "Remember the Titans" premiere, he believed at the time that the thought "didn't seem so bad."

He said asking for and accepting help was the "miracle of my life."