Niall Horan, the Irish singer-songwriter and massive sports fan, got a special behind-the-scenes look at the Irish Rugby squad's session in Portugal on August 9.

Horan, a native of Co Westmeath who shot to fame as part of the boyband One Direction, said in a special video for Irish Rugby that it was "great" to be at the session.

"I found out that the lads were gonna be around this week and we're playing a festival about an hour and a half away tonight.

"I know Robbie Henshaw quite well, fellow Westmeath man, and got in touch and asked could I come down and watch the training.

"The team have been great, it's been a very nice morning.

"Watching high level sport like this, behind closed doors, it's unbelievable.

"The intensity, the heat that the lads are playing in is just - it's unbelievable. I'm sweating standing here.

"They're putting in a proper shift against a nice Portuguese side. It's very interesting to watch how it's all being played out.

"Hopefully they can keep it going. Obviously, in Ireland, we're very excited about the prospects of this team and the World Cup and where we stand in that."

💬 "Watching high level sport like this is unbelievable."

A pleasure to host @NiallOfficial at this morning's squad session in Portugal 👇#TeamOfUs

— Irish Rugby (@IrishRugby) August 9, 2023

Andy Farrell's side was in Portugal for a warm-weather training camp ahead of next month's World Cup tournament. Also visiting with the Irish squad were Irish soccer star Roy Keane and Irish pro golfer Pádraig Harrington.

Keane, who is a big rugby fan, was invited to speak to the Ireland squad before a behind-closed-doors friendly against Portugal on Thursday and was pictured sharing a joke with Irish captain Johnny Sexton, who supports Keane's former club Manchester United.

.@JohnnySexton and Roy Keane share a joke at @IrishRugby's camp in Portugal this afternoon (📸 @DanSheridan2012)

— Inpho Photography (@Inphosports) August 9, 2023

Ireland will play two warm-up matches against England and Samoa before kicking off their World Cup campaign against Romania on September 9. 

Farrell's side is currently the number-one ranked side in the world but finds itself in a difficult group alongside world champions South Africa, Scotland, Tonga, and Romania. 

If they can emerge from that group, they are likely to face hosts France or New Zealand in the quarter-finals - the two favorites for the upcoming competition.