Rugby World Cup: Peter O'Mahony says Ireland would be lost without characters like Mack Hansen

Hansen came off the bench in last week'swin over Romania

Ireland flanker Peter O'Mahony has said he and his team-mates would be lost without characters like Mack Hansen around their World Cup squad.

Wing Hansen will make his first World Cup start against Tonga on Saturday after coming off the bench in last weekend's opening win over Romania.

The Australian native is known for his fun-loving nature which O'Mahony says the players enjoy.

"He is obviously an incredible character and good person," he said.

• Sexton starts in strong Ireland team to face Tonga

"He's been a breath of fresh air. We talk about it a lot, the squad that we have, and how important it is to fit in. Straight away we knew he was a top man.

"He is a character but above all he is an incredible athlete and one of the world's best wingers at the moment, which is a great addition to have in the squad.

"The over-riding factor is that he is a good person and has seamlessly fitted into our squad. He's been great craic and you need characters like that.

"Part of the beauty of rugby is the different characters that you meet and we'd be lost without him. We would be lost without guys like him.

"Tours like this are obviously made for being incredibly serious and it is obviously our job, and everything that goes with it, but the craic that fellas like this fella brings makes it a great place to be."

'Absolute privilege' to get first World Cup start - Hansen

Hansen said he has been asked not to take his shorts off this weekend

Head coach Andy Farrell dismissed any suggestion that Hansen had been left out of last weekend's original 23 for disciplinary reasons.

Asked by a reporter why the Connacht player was overlooked in the first instance, Farrell interjected: "Was it you who kept on asking the question last week? Where the hell did all that come from?

"Left out of the 23? No. We wanted to give someone else a game, as simple as that."

Speaking to the media after the team for this week was announced, Hansen joked that he had had "a five-minute tiff" with Farrell and insisted that he was enjoying his World Cup experience.

"It's an absolute privilege to get my first start and to do it against a really strong Tonga team is really exciting," he said.

"I was lucky enough to come off the bench and get a game last week which settled the nerves. That was nice so I can really just enjoy this week."

'I've been told to keep my shorts on this week'

Hansen is one of four changes made to the Ireland team by head coach Farrell after they recovered from conceding an early try to hammer Romania in their opener.

Hansen replaces Keith Earls on the wing, scrum-half Conor Murray takes over Jamison Gibson-Park, hooker Ronan Kelleher comes in for Rob Herring and Josh van der Flier is recalled so Joe McCarthy drops out.

"I think whatever Tonga do we know they are going to be a big, physical team," Hansen continued.

"We had a similar test against Samoa a few weeks ago [in Ireland's final warm-up match]. We know what they can do and we know what they can bring so we are excited for that.

"It is nice to have had that game a few weeks ago as it taught us a few lessons. We have just got to take those lessons from that game into this one. As you can see from the team we are not taking them lightly by any means."

Having taken his shorts off after the match in Bordeaux last week before leaving the field, Hansen was asked if he plans to do something similar again this week.

"I'm not the first person to take their shorts off after a game and I doubt I'll be the last. I've been told to keep them on this week. I'll try my hardest and see how I'm feeling."