The crowds had been gathering for days, and the red carpet was ready and waiting for the cast of Harry Potter to premiere their final film.

And fans certainly were not left disappointed when Emma Watson arrived in Trafalgar Square looking simply magical.

The 21-year-old actress brought the glamour in a floor-length tiered Oscar De La Renta ruffled gown, a dress that made her look like a fairytale princess. 

Scroll down for video

Fairytale princess: Emma Watson looked stunning in her Oscar De La Renta gown as she took to the red carpet

Leading lady: Emma Watson played to the crowd as she posed for pictures on the red carpet in Trafalgar Square

The dress was teamed with equally exquisite Boodles’ ‘Cabaret’ white gold earrings with citrine briolette drops worth £7,680 and a matching ring worth £10,670

But her smiles didn’t last long as Emma and many of her co-stars broke down while paying tribute to the final film in the franchise, Harry Potter And The Deathly Hallows – Part 2.

The actress welled up as her co-stars Daniel Radcliffe and Rupert Grint thanked fans and each other.

As Rupert took his turn to speak, Emma couldn’t contain her tears and the film’s producer David Heyman offered her his shoulder to cry on.

Tearful: Emma couldn’t help but break down as other cast members spoke about the film

As Rupert pays tribute to JK Rowling, Emma is comforted by the film’s producer, David Heyman

Touching scene: The tearful actress was also comforted by Rupert and she rested her head on his shoulder

She clung onto him and in turn he gave her an affectionate kiss on the head, proving just how close the cast and crew members have become.

Earlier the scene was very different and shortly after Emma’s arrival on the red carpet Harry Potter himself, Daniel Radcliffe, appeared looking dapper in grey suit and appeared to be overwhelmed by the response of the crowd.

Final call: The three main stars of the Harry Potter films, pose together for the final time on the red carpet

Setting the scene: Fans in Trafalgar Square could watch all the action live on a big screen and the famous trio also posed together on the top of the steps in full view of the crowds

In demand: Emma posed for pictures in her ice blue gown while crowds watched on

Speaking with his co-stars Daniel said: ‘I don’t think the end of the story happens tonight because each and every person who will see this film will carry this story with them through the rest of their lives.’

‘A huge thank-you to all of you, first of all for giving me a job, and Jo for letting him give me a job.’

‘Every opportunity I get from now on all goes down to the fact I got very, very lucky when I was eleven.’