Amanda Bynes has reportedly entered rehab.

The 'She's the Man' actress, who has been receiving treatment under a psychiatric hold at the UCLA Medical Center in Los Angeles in recent months, is thought to have left the hospital some weeks ago and is now seeking help at a rehab centre in Malibu, California.

Amanda, 27, raised concerns about her mental well being following her erratic behaviour in public and on Twitter earlier this year. The former child star was eventually taken into involuntary care when she attempted to set her neighbour's driveway on fire in July - an incident in which she accidentally set her trouser leg alight and doused her pet dog in gasoline.

TMZ reports Amanda has been residing at The Canyon rehab facility for ''three weeks'' and has displayed erratic behaviour in her time there.

The actress is reportedly ''paranoid'' about being pictured by the paparazzi and has interacted ''very little'' with other patients. A source added she ''rarely leaves the area where she's living''.

Troubled Amanda hit the headlines earlier this year for her strange behaviour, such as insulting fellow celebrities by branding them ''ugly'' in bizarre Twitter rants and sporting different coloured wigs while out in public.

In May, the 'Hairspray' star was arrested for possession of marijuana at her New York City apartment and was also charged for attempting to throw her bong out of a window.