Sisters Elena, 11, and Clara, 9, from County Galway, set up their CupcakeSurpriseToysTV YouTube channel three years ago.

They play pranks and challenge each other, and have already amassed 817,000 subscribers and more than 302 million views.

Elena says their acting background and love of storytelling with toys inspired them to create the channel, where they regularly work with brands such Mattel and Moose Toys.

"We were watching YouTube videos anyway and so we thought, why not put it to good use and make a YouTube channel?"

So how does it feel to have millions of views?

"It feels awesome, it's a great sense of achievement," says Clara. "We work really hard on the videos. It's nice when fans come up to us when we're out shopping and say 'we know you'."

Still, their mother Emily Brady, who works full-time on the channel, says it can be hard work.

"People underestimate the time involved [in making the videos]. There's a lot of preparation needed."

A survey by travel firm First Choice found that 34% of six-to-17-year-olds would like to be a YouTuber when they grow up. And almost a fifth (18%) said they would like to be a blogger or vlogger [video blogger].