Demi Lovato is set to star in a new YouTube Originals documentary series.

The 27-year-old singer will be the subject of an as-yet-untitled four-part series with the streaming service, which will follow her life over the past three years.

The series - which is being directed by Michael D. Ratner and produced by OBB Pictures - will cover her near-fatal overdose in 2018 and her journey back to full health and sobriety, as well as key events including her landmark performance of the National Anthem at this year's Super Bowl.

For Demi, the series comes three years after she teamed up with YouTube to release 'Demi Lovato: Simply Complicated', which tackled her struggle with addiction and her initial journey to sobriety before her 2018 relapse.

In the documentary, Demi spoke openly about her trip to rehab in 2010, where she admitted she would smuggle drugs into the treatment centre because she ''wasn't ready to get sober''.

She said: ''I wasn't working my program, I wasn't ready to get sober. I was sneaking [cocaine] on planes, I was sneaking it in bathrooms, sneaking it throughout the night ... I went on a bender of like, two months where I was using daily.''

The 'Anyone' hitmaker also said there even came a point where she feared for her life after she took a ''bunch'' of cocaine.

She explained: ''There was one night when I used a bunch of coke and I popped a few Xanax bars, and I began to choke a little bit. My heart started racing, and I thought to myself, 'Oh my God, I might be overdosing right now'.''

Meanwhile, Demi recently said it is a ''sign of strength'' to seek help with your mental health.

She said: ''It's so important that people have these lines because sometimes you feel really alone and you don't know where to turn or who to talk to. You're afraid that these thoughts you're having are too dark, and you need guidance. That's where this comes in. It can provide help to people who are struggling. Asking for help is not a sign of weakness. It's a sign of strength. Oftentimes our society tells us that if we ask for help, we are weak. But the strongest thing someone can do is take that first step in getting help, whatever shape or form that is.''