Billy Joel doesn’t want to “dilute his legacy” by putting out music past his prime.

The legendary musician, 77, explained why he quit writing songs after his 1993 album “River of Dreams” in a YouTube interview with music producer Rick Beato released Monday.

“I’ve heard artists who keep putting out records and, really, they’re past…” he candidly said. “They dilute their legacy.”

“Maybe they’re not as good as they used to be or they’re not as motivated as they were, but it ends up trailing off,” he continued. “I didn’t want to go like that.”

He added, “It’s not easy to do. Saying no sometimes is really hard to do.”

“I didn’t want to just keep beating a dead horse and being played because I was Billy Joel,” he explained. “I wanted it to be good, and I recognized that I didn’t have the same motivation I used to have, so I said, ‘Stop.’”

Joel said he felt “done” after writing “River of Dreams” — his 12th studio album — noting he was married to supermodel Christie Brinkley at the time and they had a child. Joel was referring to his eldest daughter, Alexa Joel, now 40.

“I didn’t want to lock myself in a cave and devote myself like a monk to writing anymore,” he admitted. “I had done it 12 times and I thought, ‘You know what? The Beatles had 12 albums.’ And that was just enough for me.”

The “Uptown Girl” singer shared that he recently couldn’t even give a songwriter from a new band any help when he asked for it.

“I go, ‘Well you’re gonna have to fix it because I can’t do it anymore,’” he noted. “‘You better learn how to stop songwriting because it’s gonna drive you crazy. You’ll go insane. You get to a point you can’t do it anymore.’”

“‘You’ve tapped it out, you reached such a high level that you can’t stand not reaching that level anymore and you hate yourself,’” he continued. “You beat yourself up, and I don’t want to put myself through that anymore.”

Though Joel and Brinkley split in 1994 following nine years of marriage, the two are still on good terms.

In April, the model shared a health update on Joel a year after he was diagnosed with the rare brain disorder Normal Pressure Hydrocephalus (NPH). The disorder occurs when cerebrospinal fluid (CSF) builds up inside the skull and presses on the brain, disrupting cognitive functioning, per the Cleveland Clinic.

Brinkley, 72, said Joel was “doing well” at the time.

“I’m so proud of him,” she told Hello! Magazine. “He’s such a trooper, so resilient and committed to being healthy and proactive. He’s a fighter. He’s always been a fighter and talks in his documentary about how life’s like a fight.”

The Grammy-winning singer married his fourth wife, Alexis Roderick, in 2015. They share two daughters together — Della Rose, 10, and Remy Anne, 8.