Singer George Michael has reportedly checked into a rehabilitation centre in Switzerland following a battle with substance abuse.

The 51-year-old star has apparently entered the facility because he was smoking "as many as 25 joints a day" before deciding to seek help at the Kusnacht Practice, reported Daily Mirror.

The "Faith" hitmaker had previously said a series of health scares and trouble with the law had convinced him to quit using the drug.

"I decided to change my life and I haven’t touched it."

The treatment reportedly costs around 100,000 euros and has previously been sought by other famous names, including designer John Galiano.