The 41-year-old actress stopped by Jimmy Kimmel Live! on Thursday, where she shared a hilarious PSA on how to tell her apart from the Oscar-nominated star.
"Hello, I'm Isla Fisher and I’d like to clear something up. I am not Amy Adams," Fisher began. "Amy Adams and I are completely different people. Let me explain. Amy Adams has auburn red, my hair is light auburn red. Amy Adams played Susan in Nocturnal Animals. I played Laura in Nocturnal Animals. Amy Adams has five Oscar nominations. I am a member of SAG."
During her appearance on Kimmel, she brought that story up again, elaborating on what happened when the "Born This Way" singer praised her for her performance in American Hustle,thinking she was Adams at the 2014 Vanity Fair Oscar party.
"I was there, all excited and dressed up at the bar and, you know, schmoozing with showbiz types, and the crowds parted and there was Lady Gaga,” Fisher recalled. “And she's heading right toward me and she says, 'Thank you. Your performance in American Hustle, Amy, was...‘ And I’m thinking, Oh my gosh, it’s Lady Gaga. I love her so much. I don't want to tell her the truth. So I just gracefully thanked her, bowed my head."
"And then she wants to talk about the performance, and now I’m thinking, I don’t want to be a liar,” the Keeping Up With the Joneses star continued. “And then I look over her shoulder and there’s Amy Adams walking into the party. So I’m like, 'There’s Isla Fisher.' I said, 'She’s not even nominated for anything. What’s she doing here?'"
Fisher doesn't mind being mistaken for Adams. Last year she told ET, "I find it a huge compliment because I think Amy's gorgeous."
See more of what she had to say in the video below.