Reformed drug addict Tatum O’Neal has been arrested for relapsing and buying crack from a New York drug dealer.

The Oscar-winning former child star, who chronicled her recovery from a heroin addiction in her 2004 book A Paper Life, was spotted by a narcotics team exchanging money with a man three blocks from her home in the Big Apple.

The actress, daughter of actor Ryan O'Neal, initially told cops she was "doing research for a part", according to a police source.

But, after authorities searched her and found two bags of drugs and a crack pipe, she changed her story, the source adds.

According to the New York Daily News, she pleaded with cops: "I've been clean for a long time. Today was the first time I was relapsing, but you guys saved me! Can you let me go?"

The Paper Moon star, 44, was charged with seventh-degree criminal possession of a controlled substance, a misdemeanour.

The incident comes just eight months after the star publicly urged singer Britney Spears to seek "recovery and get her disease of addiction together".

O'Neal became the youngest ever Academy Award winner at the age of 10, when she won Best Supporting Actress for her role in Paper Moon.