BEFORE competing on “Survivor: Blood vs. Water,” Vytas Baskauskas battled a heroin addiction and spent a year behind bars!

But the 33-year-old managed to turn his life around, and he’s now a popular Los Angeles yoga instructor and math professor.

“After experimenting with many substances and heightened states, by the time I was 17, I found myself addicted to heroin,” Vytas admitted.

“Within two years, I was homeless, strung out, emaciated and ready for a change.”

Vytas joins the hit CBS show for its 27th season, which pits returning castaways against family members or significant others.

He’ll compete against his 31-year-old brother Aras, who won “Survivor: Panama” in 2006.

“Everyone, especially his brother Aras, thought Vytas was going to die a homeless junkie,” a family friend told The ENQUIRER.

Now 14 years sober, Vytas credits yoga and meditation for saving him.

The source added: “Vytas has come a long way, and he wants people to know that if he can bounce back from a life of drugs and crime, anyone can.”