Niall Horan
Niall Horan got a welcome surprise last weekend when he saw the Backstreet Boys perform in London’s O2 arena and they played “What Makes You Beautiful!”.

Some lucky female fans were serenaded by the pop group as they played the One Direction hit over the loudspeakers during the concert.

After the show the Westmeath man tweeted: "Hahaha they play WMYB in the concert! hahaha! brilliant!" [sic]

The only Irish member of One Direction then got to meet the famous American pop band back stage, where they posed for a photo.

Niall tweeted the photo with the caption: "amazing night! met the backstreet boys and new kids! super nice guys! got some good advice!" [sic]

In addition to hanging out with the Backstreet Boys, Horan also attended a JLS concert in Sheffield.

Enjoying their down time, One Direction returned to the UK last week after a long tour of America, Australia, New Zealand, and Canada.