American Pie star Jason Biggs has stunned fans by revealing he's one-year clean and sober after a booze and drugs binge threatened to wreck his career.

The actor took to Instagram on Thursday (11Oct18) to publicly celebrate his anniversary, revealing he had struggled for years to straighten up.

"I first tried to get sober over 5 years ago, when the weight of my obsession with booze and drugs became too heavy for me to handle," the 40-year-old father-of-two wrote. "Turns out this s**t is hard."

"After some fits and starts, I've managed to put together one year of sobriety. I'm as proud of it as anything in my life," he added, before offering a little hope to others who are struggling: "Know there’s help," he added. "Don’t be ashamed. We can do this."

Jason's wife Jenny Mollen was also celebrating - she posted a photo of the actor planting a kiss on her cheek and wrote the caption: "So proud of my husband today. Congrats baby. I know how hard you work. I see you. I love you. Thank you for your fight."

It appears Biggs' sobriety battle began around the birth of his second son, Lazlo, who entered the world on 2 October, 2017.

The couple had a tough start after Mollen suffered a miscarriage in 2008, just weeks into her relationship with the actor.

In a candid interview with People magazine months after she first became a mum in 2014, Jenny revealed she was 12 weeks along when she lost the couple's baby. Jason and Jenny eloped two months later and wed in April, 2008.