14/03/2017 18:16 GMT | Updated 14/03/2017 18:27 GMT

Viral Video Star Robert Kelly Says His Daughter Was 'In A Hippity Hoppity Mood' When She Danced In

He explains why he couldn't stand up too.

The inside story has been revealed about the sweetest viral video ever, in which a young girl gate-crashed her dad’s live and very serious interview with BBC News.

On Friday, Korea expert Robert Kelly’s face fell when, in the footage of his own interview on his screen, he saw the door behind him open and his four-year-old daughter Marion walk into the room.

She walked in a half-dancing way that caught the internet’s imagination as the clip was shared millions of times around the world.

She was followed by her eight-month-old brother James on a stroller and then their mother Kim Jung-A who darted in, pulled them out and slammed the door shut behind her.

Kelly then wrapped up answering questions about the impeachment of South Korea’s president Park Geun-hye and the interview ended.

BBC News
Marion appears as her father is interviewed

In an interview with the whole family, Kelly told The Wall Street Journal that Marion was exuberant because it was her birthday and she had had a party at Kindergarten.

“She was in a hippity-hoppity mood that day because of the school party,” he said.

Marion had been watching the interview on TV with her mother - who was filming it on her phone - and recognised the room and wandered off to find her dad while her mother was still distracted.

Wall Street Journal
Robert Kelly, Kim Jung-A and their children being interviewed by The Wall Street Journal

Kelly revealed was wearing casual jeans off camera, beneath his suit and tie and so could not stand up when Marion approached. This would explain why he remained bolted to his seat as she approached and never stood up.

He told the WSJ he wrote to the BBC to apologise as he had failed to lock the door but the broadcaster eagerly shared the clip.

Kim said: ““He usually locks the door... Most of the time they come back to me after they find the locked door. But they didn’t. And then I saw the door was open. It was chaos for me.”

Kelly said: “I saw the video like everybody else. My wife did a great job cleaning up a really unanticipated situation as best she possibly could...

“It was funny. If you watch the tape I was sort of struggling to keep my own laughs down. They’re little kids and that’s how things are... I made this minor mistake that turned my family into YouTube stars. It’s pretty ridiculous.”