Oscar-winning actor Jack Nicholson has reportedly retired from the big screen because of a fading memory.

According to Star magazine and Radar Online, the 76-year-old star of The Shining, One Flew over the Cuckoo's Nest and Easy Rider has quietly ended his long and illustrious movie career because he was struggling to remember his lines.

"There is a simple reason behind his decision - it's memory loss," a source told Radar. "Quite frankly, at 76, Jack has memory issues and can no longer remember the lines being asked of him."

Over the course of his five-decade career, Nicholson has played some of the most memorable roles of 20th century American cinema.

He received Oscars for Best Actor for his performance in As Good as it Gets in 1998 and One Flew over the Cuckoo's Nest in 1976. He also picked up the prize for Best Supporting Actor in 1984 for Terms of Endearment.

He remains the most nominated performer in the history of the Academy Awards.

2010's How Do You Know?, a romantic comedy, was his last Hollywood outing. In it, he played the father of a business executive facing jail over alleged corporate malfeasance. Reese Witherspoon and Paul Rudd were his co-stars.

"Jack has no intention of retiring from the limelight [altogether]," Radar's source said. "He's not retiring from public life at all. He just doesn't want a tribute. He's happy to tacitly join the retirees' club, like Sean Connery."

NBC News anchor Maria Shriver was said to have rubbished the reports and said that Nicholson would continue considering scripts.

According to E! Online, she asserted that he was "not suffering from any memory-related illness or dementia".

Nicholson has not commented.