London, Mar 14 : Heath Ledger's ex-girlfriends Michelle Williams and Naomi Watts were among the many Hollywood stars who paid a moving tribute to the late actor.
Williams, the mother of Heath's daughter Matilda, described the 'Brokeback Mountain' star's energetic nature and constantly working mind while speaking to Interview magazine.
"He had an uncontrollable energy. He buzzed. He would jump out of bed. For as long as I'd known him, he had bouts with insomnia," The Sun quoted Williams, as saying.
"He just had too much energy. His mind was turning, turning, turning - always turning. He had a talent for everything that he put his mind to. He didn't know limits.
"I think that the interesting thing about Heath, which maybe people have only really fully discovered in his death, his how vulnerable he was.
"You can pick up on it in his performances, but it's easy to overlook because he was so physical and beautiful and strong and masculine.
"But there was always that underlying sensitivity. That's who he was," she added.
Following Williams, Naomi, who dated Ledger for two years, said of her ex flame: "His acting was just so touching, so connected in truth. I think he was just getting started."
Philip Seymour Hoffman, Sean Penn and pal Ellen DeGeneres were among the other celebrities paid tribute to Ledger.