Robert Downey Jr. has been granted an official pardon for a drug conviction that sent him to prison nearly 20 years ago.

California Governor Jerry Brown announced pardons for 91 people who had been out of custody for 10 years and proved they had turned their lives around.

Robert Downey Jr.’s conviction will remain on his record but he will have his voting rights restored.

In 1996, police found cocaine, heroin and a pistol in the actor’s car when they stopped him for speeding.

Robert Downey Jr., who is best known today for his role as Iron Man in a series of Marvel movies, was sent to prison in 1999 after violating his probation.

The actor had achieved early success in Hollywood after making his screen debut at the age of five, but went on to fall victim to drink and drugs, before spending time in rehab and rekindling his commercial success.

A proclamation from Jerry Brown’s office says Robert Downey Jr. has “lived an honest and upright life, exhibited good moral character, and conducted himself as a law-abiding citizen”.

It went on to say the actor “has paid his debt to society and earned a full and unconditional pardon”.

Gov. Jerry Brown has issued hundreds of pardons in each of his four terms in office, usually doing it around Christian holidays.

Most people pardoned along with Robert Downey Jr. had been found guilty of nonviolent drug and property crimes.