A decade after Heath Ledger’s tragic passing, his former girlfriend, actress Naomi Watts, has paid tribute to his “beautiful soul” on social media.

“Thinking about this beautiful soul today,” Watts, 49, posted to Instagram this morning.

“Ten years ago he left this world. He was a true original. Heart always on his sleeve, with the most powerful charisma, strength, humour and talent. I will never forget his gentle spirit.”

Watts, who moved to Australia from England when she was a teenager, and the Perth-born Ledger dated for two years until 2004.

She said in 2011: “He was really a very special soul who made a great impact on my life,” Daily Mail reports. “He was a man completely filled with joy.”

A post shared by Naomi Watts (@naomiwatts) on Jan 22, 2018 at 6:57am PST

Ledger died on January 22, 2008 in his Manhattan apartment. He was 28.

Before his death, the Australian actor, who’d starred in Brokeback Mountain and The Dark Knight, was having trouble sleeping.

“Last week I probably slept an average of two hours per night,” Ledger told The New York Times in November 2007, just months before his death.

LISTEN: Bec Sparrow and Robin Bailey deep dive on grief, discussing ways to process it and how to move on. Post continues after audio.

He said his then recent work in I’m Not There and as the Batman Joker had left his mind restless. That would see him take medication to assist in helping him sleep, which left the actor in “a stupor, only to wake up an hour later, his mind still racing”.

Ledger left behind a daughter, Matilda Rose, now 12, with American actress Michelle Williams. The pair, who started dating in 2004, had separated in the year before Ledger’s death.

His cause of death was deemed “accidental overdose”.

Watts isn't the only one to pay tribute to Ledger on the 10th anniversary of his death. Social media is flooded with messages about the late actor.

Deadpool star Josh Brolin commented on Watts' photo with: "Hear! Hear! The little time that I spent with him was present, mischievous, lovely and true. I still feel the loss of such a unique, sensitive soul".

Jake Gyllenhaal, a close friend of Ledger's and the godfather to Matilda Rose, told E News:

"A friendship can't really be explained in a soundbite or a three-minute interview," Gyllenhaal, who starred with Ledger in Brokeback Mountain, said.

"Heath meant a lot to a lot of people. The people who were fans; the people who saw his work and who were moved by his work; and the people who knew him as a person. He was an incredible force and is still missed."

Another of Ledger's best friends, American actress Busy Philipps, used Instagram stories to let the world know: she's still thinking of him.

"I was just driving and I was thinking about my friend, Heath, who died 10-years ago and this song came on," she told the camera, referencing the MGMT hit Time to Pretend that was playing in the background.

"It came out after he had passed away and I remember when it came out because I thought — it made me think of him. I just thought he would have liked this song, you know? For some reason, every time I hear this song, I think of him — and I was just thinking of him. It’s weird. That’s all."

Ledger's older sister Kate told WHO Magazine in a recent interview she misses her "soul mate" every day, People reports.

"There’s not a day that goes by that we don’t share stories or talk about him. He is very much alive in our house," she said.

"We spoke almost every day regardless of where Heath was in the world or what he was doing. Our conversations ranged from talking about projects to what we were having for dinner! Nothing was off limits."

Then, there are the messages of love and grief from those who never knew him but - like Gyllenhaal said - were touched by Ledger's work:

Just a reminder that my first real love died 10 years ago today. ???? #HeathLedger pic.twitter.com/20Kdi5Te2j

— Andrea Ruschel (@andrearuschel) January 22, 2018

a legend #HeathLedger pic.twitter.com/FsucvRXmDa

— Alex Vazquez (@alexxvazquezzz) January 22, 2018

ten years with no heath ledger...rip to such a creative legend???????? pic.twitter.com/v8Nezv7mxq

— kate christensen (@katerrloo) January 22, 2018

And finally, one genius fan has re-circled footage of this iconic interview, in which Ledger was interrupted on the red carpet by Aussie comedian and actress, Magda Szubanski.

Do yourself a favour and watch it. It will turn your tears into laughter and one message is clear: Rest in peace, Heath Ledger, you are greatly missed.

does anyone else remember this iconic heath ledger interview pic.twitter.com/ng7rdujGxT

— marissa (@annoyingluna) January 22, 2018

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