Elle King, the Grammy-nominated singer of hit song “Ex’s and Oh’s,” finds that a particular contingent of people consistently doubt her talent: men.

“For a long time I didn’t understand that guys…weren’t really my friend, and they saw me as competition, and they didn’t take me seriously,” King said Wednesday at Fortune’s Most Powerful Women Next Gen Summit in Laguna Niguel, Calif. “That was the wrong move.”

King spoke about her struggles with drugs, domestic abuse, and post-traumatic stress disorder, and her journey to reconciliation with her father, the comedian Rob Schneider (known for Deuce Bigalow: Male Gigolo), and other family members after a long period when she was shunned.

“I’m very capable, I can sing just as good, if not better and louder, than a lot of men,” King said, before performing “Ex’s and Oh’s” and “Baby Outlaw” for the Fortune conference attendees.

The singer noted that men have continued to underestimate her—even after her first album, Love Stuff, achieved gold certification, and “Ex’s and Oh’s” went double platinum.

“I still get it sometimes, a lot of dudes don’t take me seriously in rock ‘n’ roll, and I think that that’s a big mistake,” she said. “And I don’t forget it. You know?”

Ironically, it was King herself who initially didn’t believe in her own potential: Her most popular song, “Ex’s and Oh’s,” actually “started out as a joke,” she said. She’d written the lyrics “about exes wanting to sleep with you again,” and “I never thought my big record label would go for anything like that.”

As it turns out, she’s proven herself wrong, too.