The upcoming musical comedy follows a plus-size teenager who enters a beauty pageant in a bid to face up to her insecurities.

• Aug 4, 2018

AceShowbiz - Dolly Parton had to stifle her giggles while sitting in on an advance public screening of Jennifer Aniston's new movie Dumplin' to avoid alerting audience members to her presence.

The upcoming musical comedy, based on author Julie Murphy's young adult novel of the same name, centres on a plus-size teenager who enters a beauty pageant in a bid to face up to her insecurities.

The accompanying soundtrack features six original tunes from country legend Dolly, and the singer recently joined Jennifer to check out the finished film in a theatre, where they went incognito, so they could gauge the audience's reaction.

The actress reveals the bubbly icon, 72, struggled to keep control of her emotions, which put them both at risk of being recognised.

"When Dolly and I watched the movie together, we were in a theatre full of people who didn't know we were sitting in the back," Aniston tells InStyle magazine. "During one of the funnier parts, she's stifling her laugh and whispers to me, 'They (fans) can't hear my laugh. They'll know my laugh'.

"A couple of minutes later I look over and she's crying, and she says, 'But they don't know my tears'."

Jennifer portrays a "fun but broken" former pageant queen in Dumplin', and she found it fascinating to research the pageant world.

"I had so much fun," she smiles. "There are women devoting their lives to training young girls for pageants, and it's the real deal. I loved those women and really enjoyed getting into the mindsets."

And getting to work with Dolly was "magic" and so inspiring: "I remember the first thing she said to me when she walked into my house," Jennifer recalls. "I said, 'I don't know how you do everything you're still doing'. She said, 'Well, I dreamed myself into a corner, and now I gotta live up to it'."