Wales coach Warren Gatland has some pressing questions ahead of the start of the World Cup next month.

It is a perennial problem that firstly troubled former Wales coach Wayne Pivac and is now in the thoughts of his successor Gatland.

Wales could rely on the Jamie Roberts and Jonathan Davies combination for the first eight years of Gatland's opening tenure in charge.

Davies was then partnered by Hadleigh Parkes during the 2019 World Cup in Japan. That continuity has disappeared since then.

Gatland will unveil yet another centre duo when they face England at Twickenham in the second World Cup warm-up on Saturday.

Scarlets centre Joe Roberts will win his first cap alongside Nick Tompkins, a week after Max Llewellyn and George North formed the midfield in the 20-9 victory over England in Cardiff.

It will be Wales' 21st centre partnership in 41 internationals since the beginning of 2020.

Joe Roberts will be Tompkins' eight starting partner after he had previously begun games alongside George North, Parkes, Johnny Williams, Owen Watkin, Davies, Willis Halaholo and Josh Adams.

Gatland has admitted he is concerned about establishing a settled centre combination. Saracens back Tompkins agrees.

"As I've said it before in passing, it's [centre combination] massively important but it is based on us as players to show we can consistently perform for them to pick that," said Tompkins, who has started 21 games for Wales.

"So it's one of those things. The coaches will want continuity and they want to build a partnership. It's on us players now to step up and show who deserves to take that shirt and be there for a long time."

Tompkins, Roberts and Ospreys centre Keiran Williams, who is set to win his first cap off the bench, are battling with Johnny Williams, Llewellyn, North and Mason Grady for probably four midfield berths in the final 33-man squad.

"The competition is pretty good for the coaches and for us because it pushes us," said Tompkins.

"It sets the tone. It's something Wales have missed over the period. They have had very set centres and that was really good, but now it's probably a lot younger and a lot more competitive, so it's exciting."

Keiran Williams, Roberts and Tompkins are smaller than fellow centres Llewellyn, North, Grady and Johnny Williams. Tompkins insists he will not be expected to match characteristics of other players.

"I am who I am and I will bring what I can bring and that's what I want to do," said Tompkins.

"I will be looking to bring all the experience I can and show what I can do."

No ordinary Joe

Scarlets midfield man Roberts is the latest centre to be given his opportunity after impressing for his region in the 2022-23 season.

"I've been impressed with him for a while, his footwork and carrying," said Gatland.

"He's big through the thighs, he's left-footed, and we haven't got any other left-footers in the squad.

"So it gives us a little point of difference in terms of kicking strategy and exit plays in how you might want to manipulate teams.

"I will be interested to see how he goes. We spoke about Keiran as well but it would have been a pretty young midfield combination.

"Nick [Tompkins] brings that experience and hopefully Keiran will get a good run there in the second half."

Tompkins echoed these sentiments.

"He's really impressed me coming in," said Tompkins.

"His footwork is phenomenal. He's fit. He's got a well-deserved opportunity and I just hope he takes it with two hands and really runs with it and shows what he can do.

"Keiran has also been phenomenal. He played against Saracens for Ospreys in the Champions Cup game and he was outstanding, a real handful of a player.

"Don't let his size fool you, he is an absolute nugget, he runs hard and has great footwork. He is going to be great coming off the bench as well."

Roberts will fill the key outside centre defensive position.

"Joe has been great over the last 10 weeks," said Wales defence coach Mike Forshaw.

"He has worked hard, and tomorrow he will get an opportunity to see what he can do. Hopefully, defensively he will come up with some good stuff for us."

Tompkins and Roberts will face England midfield duo Ollie Lawrence and Joe Marchant, who impressed last week in England's defeat in Cardiff.

"We spoke about the two centres they [England] have picked," said Forshaw.

"One [Lawrence], you have got to put the landmines out for him, and Joe Marchant is a good, solid player, chases kicks well and is a good defender.

"The experience of Owen [Farrell] and the emotion he will probably bring to them tomorrow means we will expect a little bit of everything."