As Paul McCartney and Wings performed in the early ‘70s, a family of mice got on with their lives underneath the stage. At least that was the concept behind The Bruce McMouse Show, a part-animated concert movie that was completed but never released.

It’s been so well hidden, in fact, that little else besides a handful of still drawings from the production had ever escaped from the McCartney vaults. Then the title appeared today as part of an upcoming expanded reissue of Wings' 1973 album Red Rose Speedway. That had many asking, "What was The Bruce McMouse Show?"

UPDATE: The Bruce McMouse Show will play movie theaters for one night only on Jan. 21. The screening will include the animated feature as well as live performances by Paul McCartney & Wings. Twenty cities around the world -- including New York, Liverpool and Toronto -- will show the film. You can get more information on the screenings and locations at the official site.

In the original hour-long presentation, Wings interacted with the pipe-smoking Bruce McMouse and his family, which included wife Yvonne and their children Soily, Swooney and Swat. Also featured was a blue walrus, harking back to the Beatles track “I Am the Walrus” and the assertion “the walrus was Paul” in “Glass Onion.”

The members of Wings got involved, too, with afternoons during the tour being spent filming scenes where they pretended to interact with the cartoon characters via holes in the stage and performed song-and-dance routines. "We went to a studio to learn how to do a particular dance step," the late guitarist Henry McCullough said in Peter Ames Carlin's Paul McCartney: A Life. "Old-time music-hall dancing, arms in the air and such. I don't think I ever quite made the grade."

Bruce and Yvonne were voiced by Deryck Guyler and Pat Coombes, who were British TV regulars of the day. Derek Nimmo, Paul and his wife Linda handled other characters. The animated sequences were set against concert footage shot during the Wings Over Europe tour of 1972.

“We decided that it might be boring to watch a group in action for an hour or more,” McCartney told NME in 1973. “So, we’ve added interest by incorporating a cartoon story about a family of mice who live under the stage.” The report added that the animation technique was similar to that used in Disney’s Mary Poppins, and that the musical content was made out of songs that were dropped when Red Rose Speedway was cut from a double-length LP to standard single length.

For unknown reasons, however, McCartney abruptly abandoned The Bruce McMouse Show. A song titled “Soily” later arrived as part of the Wings Over America live set, but otherwise the project essentially vanished.

Listen to Paul McCartney and Wings Perform 'Soily'

Most of the scant details surrounding The Bruce McMouse Show were revealed when Maggie Thornton, daughter of animator Eric Wylam, attempted to auction pre-production drawings made by Paul, Linda and daughter Heather in 2011. McCartney, who owns the master copy of the film, ultimately blocked the sale.

Thornton said the sketches had been with her family for decades. "My father was given a pile of scrap paper covered in rough drawings," she told The Independent, "and I always believed they belonged to him." McCartney countered that he didn't know the sketches still existed, and that they were his property. By then, Wylam had died, only a few years after finally getting to view his completed work.

Brief snippets from The Bruce McMouse Show later appeared in a pair of made-for-TV documentaries, 1986's The Paul McCartney Special and 2001's Wingspan, but otherwise it's remained one of the bigger remaining mysteries in the McCartney legend – perhaps because of quality issues. Auctioneer Chris Albury told the Daily Mail in 2011 that The Bruce McMouse Show had never been fully released because it "probably didn't stand up to McCartney's high standards."

Thornton agreed. "When [Eric Wylam] fell ill in about 1993, I wrote to Paul McCartney asking if there was a way that my father could see the finished film – and he sent the video, which my father watched," she said. “I have seen it, and I can see why it was never released. The storyline doesn't really work and some of the cutting between the singing and the animation isn't very good.”

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