Meryl Streep took a chance on Sharon Osbourne disguise to sneak into Mamma Mia preview

She may be one of Hollywood’s best-known stars, but apparently there was little knowing me, knowing you when Meryl Streep attended a screening of Mamma Mia in secret.

The audience failed to recognise the star of the film after she disguised herself as Sharon Osborne.

Streep ignored the pleas of studio bosses for her to stay away from a preview screening of the 2008 film held in Santa Fe, New Mexico, weeks before its official release, in order to avoid skewing the audience’s reaction.

However, Streep took a chance on going unrecognised by dressing as the US presenter of the X-Factor. In the end, she even fooled those sitting around her.

The bizarre ploy emerged during the Sundance Film Festival, when Phyllida Lloyd, who directed Streep in the Abba-based musical, recalled her shock at the actress’s unexpected disguise.

“Meryl had told me she really wanted to go to one of the first screenings,” she said. “But Universal told her that it would cost thousands to sort it out and told her that she had to stay away.

“They said that if she was in the cinema, people would just say that they really enjoyed it. I went along and I was sitting in the screening surrounded by Hispanic speakers and wondering how the film would come across.

“I said I’ll text Meryl with how it went, and a few minutes before it started she texted me with: ‘I’m sat five rows behind you in a Sharon Osborne wig, a baseball cap and glasses.”

It was a testament to how heavily involved Streep was throughout the entire Mamma Mia production process, including dubbing over dialogue in post-production and playing a central role in edits of her scenes.

The American actress, now 72, played Donna in the film and starred opposite Colin Firth and Pierce Brosnan, covering classic Abba songs such as SOS and The Winner Takes It All.

Lloyd said the film, which spawned a successful 2018 sequel, was designed to serve an “underrepresented audience of older women who nobody was making this sort of film for.”

“There’s a hell of a way to go in making more films for older women and when we cast the stage show, we had to fight so hard to get people who weren’t leggy or size zero,” she said.

“Some progress has been made because people want to see themselves on stage and screen but there’s so much of a way to go.”

Lloyd said that, despite some of the film’s flaws, she remained proud of it. “Looking back at Mamma Mia I feel quite proud of its clunkiness... it was as much hated as loved. Some of that clunkiness was deliberate and some of it was a cock-up. I feel like it ripped up every rule of screen musicals, which is why certain types of people absolutely hated it.”

A lot of the same film critics who “hated it at the beginning” would go on to write about sobbing at Mamma Mia 2: Here We Go Again, Lloyd added, quipping: “I have no idea why that is, but maybe it’s as they get older and the prostate gland starts kicking in.”

While Mamma Mia would go on to make more than $600 million (£432 million) worldwide at the box office, Lloyd - who also worked with Streep on the Margaret Thatcher biopic The Iron Lady - said that she “doesn’t know” whether she would make another blockbuster.

“I feel much more comfortable in the world that I’ve found myself in and I’ll have to see. On my last film [2020’s Herself] I deliberately made sure the budget was as low as possible so that I could cast whoever I wanted. I was offered all of the musicals after Mamma Mia but I’d never want to do the same thing twice.

“I’m not sure I’d do another biopic either, but come back to me in another couple of years. You can’t rule anything out.”