Xanadu show

OMG, O N-J! Olivia Newton-John laughed and clapped the loudest as she was mercilessly sent up onstage at the opening night of “Xanadu” on Broadway Tuesday night.

Star Kerry Butler’s brutal Australian accent sounds like a throttled budgie. But Newton-John whooped with delight as she garroted every vowel.

“I was so nervous she would think I was making fun of her,” Butler told me after the show. She reprises the role of a roller-skating muse in 1980 Venice Beach.

“I saw her in the audience and I was like, ‘Don’t look!’ [But] she said she loved it and she hasn’t laughed that hard in a really long time.”

Her co-star, Cheyenne Jackson, told me he started skating as a holy roller. “I went to a private Christian school and we had Christian skating nights,” he said. “Skating for Jesus.”

And does he think the show is Australian-phobic?

“Yeah,” he said after a moment’s reflection. “But I think in a fun way.” Throw another dingo on the baby!