After impressing Helen Mirren, 17-year-old Bebe Cave has wowed Cannes with her role in the dark fantasy Tale of Tales. Next: French exams

She is the new toast of Cannes, taking the part of the princess to rave reviews in one of the most celebrated films of the festival so far. 

But just the morning after her world premiere, British teenager Bebe Cave will be settling down to take her A-Level exams in a remarkable climax to a fairy tale rise to fame.

The 17-year-old actress, who got her big break starring opposite Dame Helen Mirren as the Queen, has made her first promenade down the Cannes Film Festival red carpet after winning a role alongside global stars Salma Hayek, John C Reilly and Toby Jones.

She has already received rave reviews, with the Telegraph calling her a "revelation" who gives a "performance of blistering pathos and real comic punch".

Bebe Cave, far left, in Cannes with the cast of Tale of Tales Credit: AFP/VALERY HACHE

It is a remarkable ascent for an acting career which began with her falling off her primary school stage aged five while dressed as a robot, and reached a turning point when Dame Helen Mirren advised her to dye her eyebrows.

The teenager, the youngest of five children and the granddaughter of former chief secretary to Hong Kong Sir Charles Haddon-Cave, was spotted for her Cannes role in film Tale of Tales after appearing in a YouTube video with her older sister.

She has now travelled to Cannes with her mother Debbie as a chaperone, after gaining special permission from school. To compensate for the day off, she will take her A-Level English exam in Nice, France, mere hours after she watches her own film for the first time. She prepared for the climax of her film career so far by taking two other exams at Westminster School earlier this week.

Promise: a pre-fame Bebe with her family Credit: Courtesy Bebe Cave

"I'm so happy just to be here, it's so exciting" she said of her first and only day in Cannes, after tackling a dizzying fashion photoshoot and her debut press conference.

Cave, the daughter of two GPs, could be forgiven for likening her experience to a fairy tale in its own right, after she went from self-proclaimed "unphotogenic" child to an on-screen princess.

She says a "pudding bowl haircut", "chubby" face and "terrible" teeth had left her relegated to playing a robot in her first stage production of Santa's Toybox, while others played fairies and princesses.

"In that production she fell off the stage," her mother Debbie says. "As a five-year-old you'd expect her to cry, but she got straight back up and I thought that's interesting: she thinks the show must go on."

Bebe Cave on the set of Tale of Tales: she stopped washing for two weeks to prepare for the role Credit: Courtesy Bebe Cave

From there, she went on to appear in school plays, television show May Contain Nuts, and joining an acting agency with her siblings Jessie and Ben.

In 2013, she received a big break after being cast as Princess Elizabeth in the original stage version of the audience, opposite Dame Helen Mirren.

There, Bebe said, Dame Helen gave her impromptu acting lessons, including how to walk like the Queen and how to dye one's eyebrows so facial features do not disappear on stage. 

Grim fairy tale: Bebe Cave in Tale of Tales

She now stars in Tale of Tales, or Il Racconto Dei Racconti, as the sheltered daughter of a King who is obsessed with his pet flea. Her character, who begins as a spoiled princess, goes on to be married off to an ogre, before eventually saving herself from a grisly fate.

She will see the film for the first time with her mother by her side in the Grand Theatre Lumiere, rubbing shoulders with the likes of Charlize Theron, Natalie Portman and the Coen brothers.

The actress was cast by director Matteo Garrone after he watched a YouTube video interview of her on the red carpet with her actress sister, who played Lavender Brown in the Harry Potter series.

"I had no idea even of who I was working with when I went out to Italy," she said. "It has honestly been like a fairy tale."

She was so dedicated to the role, she did not wash for two weeks to build up the required level of dirtiness, and still bears scars on her arms from being dragged around an on-set cave. 

"Everything has been so overwhelming," Bebe said of the film experience so far. "I'm very, very fortunate to have been given an opportunity like this."

She added she had been able to relate to her character as an ordinary teenager, who is "yearning for freedom" and undergoing the same kind of "angst" as her peers. 

"My character went from being naive to someone who gains a lot of strength," she said. "It's something I can aspire to, and something I can relate to. I'm sure other young people watching it will be able to as well."

When asked whether the role had put her off marriage for life, she said: "I'm still a romantic. But I'm the youngest of five, with three brothers who will never let me have a boyfriend."

The film, based on 17th century Neapolitan fables, is now on release in France and Italy. It was awarded four stars by the Telegraph's Robbie Collin, who called it a "readymade cult item" which is as "rich and all-enveloping as ermine".