Niall Horan watches 'Geordie Shore'.

Niall Horan watching 'Geordie Shore' (c) Instagram

Niall Horan watching 'Geordie Shore' (c) Instagram

The One Direction heartthrob has let slip his guilty pleasure after posting a video on his Instagram account of an episode of the MTV reality show playing on a laptop.

Niall revealed he and members of the group's band were catching up on the latest series of the show while taking some time out from their busy touring schedule.

Referring to 'Geordie Shore' cast member Scott 'Scotty T' Tomlin, he wrote: "Watching Geordie shore with @jonshone @thedanrichards and @sandybeales .... Always guaranteed a good laugh out of Scotty T ! #besttourbusever (sic)."

The 21-year-old star's confession comes after he was reported to have secretly dated Scotty's fellow reality TV star and 'Made In Chelsea' beauty Louise Thompson in 2013.

A source said at the time: "Louise has been dating Niall - they've seen each other lots and talk all the time. But it suited both of them for their nights together to be secret. He'll sneak her into his house in north London, often when it's dark.

"She makes sure she doesn't do anything around Chelsea to try and keep the romance away from the prying eyes of her co-stars on the show."

Louise, 25, appeared to confirm the romance when she confessed to her co-star and boyfriend at the time, Andy Jordan, that she'd cheated on him.

Andy later addressed the issue, saying: "I'm pretty annoyed with Niall. He sends a car to take my girlfriend back to his place? What am I supposed to do? ... I'd love to ask Niall exactly what happened and why he did it."