LOS ANGELES ? Oscar-winner Nicolas Cage is suing his former business manager for $20 million, accusing him of leading the actor "down a path toward financial ruin," court documents showed Friday.

Cage, whose finances have been the subject of several recent reports about alleged debts, accused manager Samuel Levin of exposing him to a string of risky investments resulting in "catastrophic" losses.

The claims were made in a lawsuit filed in Los Angeles County Superior Court and published by the TMZ.com entertainment news website.

The 45-year-old star -- who remains one of the most bankable actors in Hollywood after a long career that has included several hit movies -- said Levin was to blame for an unpaid tax bill set at six million dollars.

Cage said in the suit that he only learned of "the gravity of his financial condition" after firing Levin earlier this year.

The suit also alleges Levin was guilty of "over-extending [Cage's] line of credit with banks and financial institutions."

Levin is also accused of concealing Cage's "true financial condition prior to investments and assets being acquired by (Cage)."

In a seven-year period, "Levin placed Cage in numerous highly speculative and risky real estate investments, resulting in Cage suffering catastrophic losses," the lawsuit alleged.

Cage, the star of films such as "Leaving Las Vegas," "National Treasure" and "Face/Off", revealed earlier this year that he was selling off his castle in Bavaria, southern Germany, due to financial pressures.