Bridget Jones, who is played by Renee Zellweger, attends an Ed Sheeran gig in the movie and later enjoys a private audience with the British singer, who spent a day filming his small speaking role in a bar.
Sharon, who directed the 2001 original and the third, managed to secure Ed by chatting to one of the bosses of his label Warner Music, whose children went to same school as her own.
"I said, 'Oooh you've got Ed Sheeran, you think he might possibly be in our film?'" she told WENN at the premiere on Monday (05Sep16). "My kids love Ed Sheeran, I love Ed Sheeran, my mum loves Ed Sheeran, so I thought 'fantastic'. He said, 'Well, I'll ask, I don't know, I'll see what I can do.'"
When she was finally given the green light for the cameo, she immediately thought "Christ, can he act?" but her mind was soon put at ease when Ed came onto set.
"He can! He can sing, he can act, a very decent human being, lovely to everyone on set," she said. "We all fell in love. I'm sad he's not here tonight so I could get a dance!"
Sharon wasn't the only one to praise Ed - both Renee and franchise newcomer Sarah Solemani, who plays a presenter on Bridget's TV show, had kind words to say about the time the trio spent together.
"That (scene) was kind of fantastic," Renee said. "He's a very special person. So talented, no audio (auto) tune there, that guy (has) got the chops," while Sarah said Ed, 25, sang to her for six hours and she "got the hype".
The film, the follow-up to 2004's Bridget Jones: The Edge of Reason, is Ed's first movie part. However, he has a few TV cameos already under his belt including an appearance on Australian soap opera Home and Away, U.S. sitcom Undateable and drama show The Bastard Executioner.