Creepy casino tycoon Steve Wynn allegedly pressured a grandma working in one of his casinos into having sex — saying he had “never had a grandmother before” and wanted “to see how it feels,” according to a new report.

“I did it willingly, because I felt like I had to,” the unnamed granny told the Las Vegas Review-Journal. “I didn’t really want to. I was afraid for my job.”

The woman, now 71, was working as a waitress at The Mirage and was a single mom of eight who’d just welcomed her first grandchild in the late 1980s when Wynn, now 76, allegedly slept with her and sexually harassed her for around a year, the paper reports.

“You have so many new and young girls to choose from, and you know having sex with you makes me feel terrible,” the grandmother told Wynn, according to a colleague. “Why don’t you just leave me alone?”

She claims he started by singling her out and slapping her butt in public, then told her to come to his hotel room, where he asked her for oral sex. After that, they had sex many more times, she says.

“He didn’t force me or anything, but I did go,” she told the Review-Journal. “But I felt so uncomfortable.”

The allegations first came to light in a 1997 lawsuit, when 11 Mirage waitresses sued for discrimination over Wynn ordering them to lose weight so they’d look better in their uniforms.

The Review-Journal itself was planning to report on the claims in 1998, but the newspaper killed the story, the paper also revealed Monday.

Two decades later, the Wall Street Journal last month reported that dozens of former Wynn staffers say he’s sexually harassed workers and coerced them into sex — including one manicurist who reportedly received a whopping $7.5 million settlement.

The 1997 lawsuit also included claims that a waitress was sent to “accommodate customers sexually” in the gaming complex’s luxury villas, the paper reports.

Wynn, who didn’t respond to the Review-Journal’s request for comment, sold The Mirage to MGM in 2000, and the casino had settled all the waitress’ claims by 2003 — although the grandmother never filed a complaint.

“I didn’t even think about it,” she says now. “To me, that’s how it was. To me, it was normal.”

Wynn resigned from his post as the Republican National Committee’s finance chair following the Journal report, while his company’s board and gaming regulators in several states have opened probes into the allegations. Wynn has denied those accusations.