The 30-year-old actress has always been open about her sexuality, saying she never came out because "I was never in." However, she admitted that having the public come to terms with her choices was hard in the early days of her career.
"It did impact my career, it was difficult," People reports Heard telling The Economist's Pride & Prejudice Summit in New York City on Thursday. "It was not easy. I was the only one working in this way, so it was definitely difficult because no one had done it. I did that even though everyone told me it would end my career, without a doubt."
Heard added that her response to directors who doubted whether a bisexual actress could credibly play a straight woman was to prove them wrong.
"I rolled my eyes at that," said the "Aquaman" actress. "And I said, 'Watch me do it.' And, I did it."
Heard caused a media frenzy during her messy divorce from Hollywood star Johnny Depp last year, but in the early days of her career it was her romance with Tasya van Ree which proved an eye-opening experience.
While Heard would frequently take Ree to events and was open when asked who was her date for the evening, she says "no one ever asked" much about her love life. However, after the pair split following four years of dating and Heard told a reporter it "definitely was a big deal," she says public perception of her changed.
"Then I saw I was attached to a label," she said. "I never saw myself defined as one particular thing or not. So, I watched as I quickly became not actress Amber Heard, but out lesbian Amber Heard."
Defying those who told her she couldn't be open about her sexuality while succeeding in Hollywood, Heard has gone on to star in films including "Pineapple Express," "The Rum Diary," and "Magic Mike XXL."
|Amber Heard talked about her sexuality at a summit. (Reuters)|
Amber Heard reveals she was warned coming out as bisexual would end career
Danish Girl actress Amber Heard has said she was told revealing her bisexuality would end her movie career.
Johnny Depp's ex-wife said film-makers doubted whether she could play a straight woman in a romantic lead role after she revealed her sexuality seven years ago.
Speaking at The Economist's Pride & Prejudice event in New York, she said: "It did impact my career, it was difficult.
"It was not easy. I was the only one working in this way, so it was definitely difficult because no one had done it.
"I did that even though everyone told me it would end my career, without a doubt."
The 30-year-old said she has never hidden her sexuality and did not make any big "coming out" announcement as has been reported.
"When I hear someone comment about me coming out, I think it's funny because I was never in," she said.
Heard said she was asked directly about her sexuality by a reporter at the time and she answered "honestly" and "off the cuff".
"Then I realised the gravity of what I had done," she added.
"I started to understand why so many people - studio execs, directors, advisers, agents, producers - why everyone was so adamant about this not being the label that comes before my name.
"I quickly became, not actress Amber Heard, but out lesbian Amber Heard."
Heard was in a relationship with photographer Tasya van Ree and then began dating Depp after they met making the 2011 film The Rum Diary.
They married in 2015 but she filed for divorce the following year, amid claims of domestic violence.
Depp vehemently denied he had been "verbally and physically abusive" throughout their four-year-relationship.
Under the divorce settlement she dropped a claim the Pirates of the Caribbean star had assaulted her.
In a joint statement issued at the time, they said: "There was never any intent of physical or emotional harm".