Demi Lovato has hit out at celebrities who glamourise drug use.

The 'Skyscraper' singer - who has struggled with marijuana and cocaine abuse in the past - hit out against filmmakers, singers and other stars in a post on Twitter, in reaction to the news of Philip Seymour Hoffman's death from an apparent heroin overdose, which was discovered yesterday (02.02.14).

She wrote: ''I wish more people would lose the stigma and treat addiction as the deadly and serious DISEASE that it is. Drugs are not something to glamorize in pop music or film to portray as harmless recreational fun. It's not cute, ''cool'' or admire able ...

''It's time people start really taking action on changing what we're actually singing/rapping about these days because you never know if you could be glamorizing a certain drug to a first time user or alcoholic who could possibly end up dead because they end up suffering from the same deadly disease so many have already died from. This stuff is not something to mess with. (sic)''

Demi doesn't mention any stars specifically, but artists have written songs and made films about drug use in both positive and negative ways from The Beatles' 'Lucy in the Sky with Diamonds' in the 60s to Quentin Tarantino's movie 'Pulp Fiction' in 1994 to Miley Cyrus singing about ''dancing with Molly'' - referencing a slang term for drug MDMA - in her hit 'We Can't Stop' last year.

Former 'The X Factor' judge Demi also added a tribute to Philip - who was just 46 and leaves behind a partner and three children under 11 - in her message.

She wrote: ''RIP Philip Seymour Hoffman.. An INCREDIBLE artist who lost his life to this horrible disease.. May you rest peacefully and in complete serenity now that your pain is gone. God Bless. (sic)''