John Travolta has become an expert on the Broadway musical The Little Mermaid, say reports.

According to the New York Post, the actor sang along with all the words at a recent production.

The Pulp Fiction star took his daughter Ella, 8, to the theatre and apparently displayed an in-depth knowledge of the musical when he went backstage after the show.

"He was touching all the costumes, he looked amazed. He said he was way, way into the show. He stayed backstage for a while," said a source.

A representative for Travolta commented: "His daughter loves the show, so he knows it well."

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