Actor Dennis Hopper, shown Oct. 5, 2009, in New York, is said to be too ill to receive chemotherapy for prostate cancer. (Evan Agostini/Associated Press)

Easy Rider star Dennis Hopper is so ill he can no longer undergo chemotherapy in his battle with prostate cancer, according to his attorney.

Joseph Mannis called the actor terminally ill in a court filing Wednesday in connection with divorce proceedings against his wife, Victoria Hopper.

Hopper weighs barely 100 pounds and doctors say he is too weak to be questioned by his wife's attorneys, the court filing said.

A deposition in the court case "could actually threaten his ability to survive his current health crisis," it said.

Doctors have cleared his appearance in Los Angeles on Friday so he can receive a star on the Hollywood Walk of Fame.

The filing updates an earlier declaration in which the actor said he was hopeful that treatment would be successful and he would resume his normal life.

Hopper, 73, and his wife have ended their 14-year-old marriage with a bitter divorce battle and agreed earlier this year to stay at least three metres away from each other while the dispute is being resolved.

The veteran actor's movie credits ranged from early successes such as Rebel Without a Cause and Gunfight at the O.K. Corral to the 1960s classics Cool Hand Luke and Easy Rider, which he also co-wrote and directed. More recent hits included Apocalypse Now, Rumble Fish, Blue Velvet and Hoosiers.

With files from The Associated Press