IT was the kiss that broke a million hearts as Harry Potter's Daniel Radcliffe and Katie Leung locked lips in a coming-of-age moment for the famed boy wizard.

Katie was only 16 when she landed the part of Cho Chang in the record-breaking movie franchise based on JK Rowling's books.

The Motherwell-based teenager auditioned after her father spotted an advert for the Harry Potter and the Goblet of Fire casting call.

Katie was selected from more than 3,000 hopefuls and catapulted to stardom.

Fast forward to the present day and Katie, 28, sits in a Glasgow hotel looking adorably like a fawn caught in the headlights.

"I was so innocent and naive," she muses, reflecting on that pivotal early role.

"I think that allowed me to enjoy the moment of being a teenager, part of this massive franchise and not really having a worry in the world.

"If I was given the chance to go back and re-live it, I would probably try to absorb everything around me a bit more."

A decade has passed since Cho Chang kissed Harry. In the years since then, Katie has completed degrees in photography and drama.

Her high-profile roles include playing an illegal Chinese immigrant in Channel 4 series, Run, and most recently a North Korean defector in You For Me For You at the Royal Court Theatre in London.

Katie will next grace our screens in BBC drama, One Child, which airs on Wednesday.

She plays, Mei Ashley, a student living in London who was adopted as a baby from a Chinese orphanage by a British-American couple.

Out of the blue, Mei gets a message that her birth mother, whom she has never met, urgently needs help. Mei's brother has been wrongly accused of murder and faces the death penalty.

The powerful tale is set under the shadow of China's controversial One Child Policy, a population control method introduced in 1978 and phased out only last year.

One Child was filmed in the UK and Hong Kong, the latter somewhere to which Katie has strong ties. Her father Peter was born in the city and it is where her mother, Kar Wai Li, still lives.

"I know Hong Kong well, especially where we filmed in Tai Po," she says. "It felt nostalgic to be there. I have been going back and forth since birth. My gran has a flat there too. It is almost like home."

These days Katie is based in Glasgow, sharing a flat in the city centre with her boyfriend Eric, 26, who is a close friend of her younger brother Jonathan.

Her parents divorced several years ago and her father, who owns a Chinese food wholesale firm, has since re-married. Katie has three half-siblings Nichole, 16, Darren, 14, and Will, seven.

She has maintained a loyal following since starring in the Harry Potter films.

"It has been incredible because the fans I got to know and love from the beginning have been with me throughout my career," she says.

"They come to see my plays and contact me through social media. When they go to one of my shows that isn't Potter I get really excited. They have been so supportive and I'm grateful for that."

But not all of the diehard "Potterhead" fanbase embraced Katie.

There was a contingent who, envious of her playing Daniel's love interest in Harry Potter and the Order of the Phoenix, waged a hate campaign, including creating an "I Hate Katie" website.

"Looking back I can't remember much about that part of it because I was so in denial of what was happening," she admits.

"I put it to the back of my mind. I don't know if that is the best way to deal with it, but that is naturally what I did in order to move on and be a good actor.

"I was being judged purely on my looks because she [Cho Chang] is supposed to be a very beautiful girl," she adds. "This all happened before the films even came out.

"I thought: 'Well, I can't do anything about the way I look, so I'm going to need to do the best acting to make up for it.'"

That can't have been easy. Lesser mortals would have curled up into a ball and wept.

"Especially at 16," she admits. "But I look back and I'm pretty impressed with how I did handle it."

For a time after the Harry Potter films, Katie was unsure about pursuing acting and considered a career in photography. "I love photography but I'm glad I'm doing acting," she says.

Discussing her hobbies outwith work prompts Katie – a self-confessed video game geek – to break into embarrassed laughter.

"Oh God, I'm so boring," she says, with an apologetic eye roll. "I spend most of my time playing Call of Duty.

"I used to have a head set when I played against my brother and his friends [online] but now one of his friends [Eric] is my boyfriend, so we live together and we play video games together – we don't need the headsets anymore."

She paints a blissful picture of coupled-up life. "We watch a lot of Netflix and Amazon Prime, drink red wine and eat cheese in our pyjamas. There's lots of chocolate involved," says Katie.

"We want a dog, but we're waiting until we find a lovely place with a nice park nearby."

Katie exudes steely resilience and sunny optimism – a winning combination.

"Perseverance is important. Rejection is the biggest thing I've had to overcome, but that happens to all actors," she says.

"It doesn't get easier but you learn to appreciate all the rejections – and the jobs when they come. I'm learning to embrace everything that comes my way."

One Child begins on BBC Two this Wednesday at 9pm. Thanks to Hotel du Vin at One Devonshire Gardens (hotelduvin.com)