Star Trek star Zachary Quinto has much reason to celebrate today.

Taking to Instagram on Sunday, the actor expressed his gratitude for four years of sobriety.

"Four years sober sun-kissed selfie,"

Star Trek star Zachary Quinto has much reason to celebrate today.

Taking to Instagram on Sunday, the actor expressed his gratitude for four years of sobriety.

"Four years sober sun-kissed selfie," the 42-year-old actor wrote, accompanying a shirtless selfie complete with a gold chain. "Grateful for today!"

Last year, Quinto celebrated his third year sober with a similar post. "When I think about how far I've come and how much I've grown and how much more I love myself... I'm really blown away," he wrote in 2019. "Very far from perfect - but perfectly flawed. and working every day to honor and realize my full potential."

In celebrating his milestone, Quinto explained that before getting clean, he had lost connection to feelings of gratitude, but said he's since recovered his appreciation for his friends, support and the freedom of life's journey.

The NOS4A2 actor has seldom been shy about his struggle with addiction.