Lions head coach Warren Gatland has backed Ireland duo Bundee Aki and Robbie Henshaw to hit the ground running when they renew their long-standing centre partnership against Japan on Saturday.

Gatland reserved special praise for Henshaw, who he believes has developed into a 'world-class midfielder' since the Lions tour to New Zealand four years ago.

All seven Irish Lions will feature at Murrayfield this weekend, as Conor Murray, Iain Henderson, Tadhg Beirne and Jack Conan join Aki and Henshaw in the starting XV, while Tadhg Furlong is primed to make an impact off the bench.

Aki and Henshaw have been tipped to start the Test series in South Africa, with Gatland excited about the potential of the pair linking up in a Lions jersey for the first time.

"That combination obviously goes back to the Connacht days," Gatland said.

"It's the two Connacht lads coming together and I think they are obviously great mates as well, so that kinda helps.

"A lot of people sort of see Bundee as someone, and we know he is capable of getting the ball across the gain-line, but he's got a lot more than just that to offer.

"He has got some real rugby skill, some great footwork and a passing and offloading game. So, we are expecting some real quality rugby out of both of those two men.

"I thought Robbie was the outstanding midfielder in the Six Nations. He's great in the air. I have seen him develop, improve and mature from four years ago. That's been probably one of the biggest highlights for me just in terms of how he has developed into an absolute world-class midfielder.

"We are expecting a lot from both of those and I think they are expecting a lot from themselves as well."

Beirne will make his Lions debut wearing the No 6 jersey, as Gatland made it clear that he and the coaching staff are viewing the Munster man as a back-row for the upcoming tour.

The 29-year-old has played most of his rugby in the second-row since returning to Ireland, but his versatility and energy from the flank is seen as a huge asset.

"He has been very, very good. We are probably at this stage looking at him as a back-rower," Gatland said.

"We know he can cover the second-row but I spoke to him the other day about 'What's your point of difference?' And he knew straight away what his point of difference is.

"His point of difference is his ability at the breakdown and turnovers and the amount of turnovers that he creates in a game is pretty special for a player.

"We are looking for players to think about what their points of difference is. For Tadhg, that definitely is a big part of his game – the amount of turnovers he is able to create.

"Those sorts of things can change a game and you need players like that to be able to have an impact in a match. He is able to do that and hopefully on the weekend he gets a chance to demonstrate some of those abilities that he has."

Meanwhile, a decision has not yet been made as to whether Test caps will be awarded to the Lions players for Saturday's game against Japan.

Although every player will be awarded a Lions cap and a player number, the Lions' board, in consultation with the '1888 Club', made up of former players, will decide at a later date if a Test cap will also be awarded.

“We’re playing an international side so, for me, we are playing a Test match,” Gatland added.

"Those sorts of decisions are out of my hands in terms of they are for the board to make, but I can tell you we’re playing a quality international team that we thoroughly respect.

"They made the World Cup quarter-finals, so we are preparing for a Test match, as far as we are concerned, from a playing point of view and a team perspective."