Naomi Watts and Lily Cole have paid tribute to late Brokeback Mountain actor Heath Ledger on the 10th anniversary of his death.

The Australian actor died of an accidental overdose of prescription drugs in January 2008. He was 28.

Watts, who once dated Ledger, posted a picture of the late star on Instagram, saying she would “never forget his gentle spirit”.

She wrote: “Thinking about this beautiful soul today. 10 years ago he left this world.

“He was a true original. Heart always on his sleeve, with the most powerful charisma, strength, humor and talent.

“I will never forget his gentle spirit. #heathledger? @wattsupphoto.”

Cole appeared in Ledger’s last film, The Imaginarium Of Doctor Parnassus.

She said on Instagram: “I can’t believe it’s ten years since the world lost this most beautiful spirit.

“Heath was so funny, so kind, free minded and creative, playful, so generous and a hundred other positives.

“I feel lucky to have known him, and join the list of so many who miss him.”