The pair will no doubt have a big part to play in South West London as they go head-to-head with Twelvetrees and inform Northampton star Luther Burrell but their colleague from the summer Lions tour of Australia insists he won't be backing away from the physical challenge that lies ahead at the weekend.
"They are a formidable partnership and they have proven that over the last couple of years for the Lions and Wales. They have done incredibly well, they are always making breaks and always making big tackles," said Twelvetrees.
"What struck me was how professional they were. On these tours you mix with guys and you want to learn off them. You pick up traits.
"Jamie is a top-class player and he's always making breaks and getting over the gain line. But you have to beat your opposite number - it's about the physical battle and winning the gain line. You get big guys running at you all day, so you have to put your body on the line.
"Whichever team wins the gain line and dominates the defensive line will win the game. From our point of view, it's about hitting them low and stopping them going forward.
"As a team we will look forward to the challenge and we are confident within ourselves. We pride ourselves on our defence and these are the games you look forward to - especially at Twickenham. It's one we can't wait to get to."
England were hugely impressive in coming back from behind to beat Ireland a fortnight ago, with Twelvetrees and Burrell shackling the creativity of veteran Ireland centres Brian O'Driscoll and Gordon D'Arcy in a tight encounter that followed Wales' defeat to the Irish in Dublin.
And, while Roberts and Davies may pose a different, more physical threat than their Irish counterparts, Twelvetrees insists that it will be a case of more of the same as far as he is concerned in Round 4.
"We are obviously aware of the threats that Wales pose. We were equally aware of the threats Ireland posed - they moved the ball around very well against us and it was difficult. But I thought we coped with it very well and it will be exactly the same this Sunday if we focus on ourselves, nullify the big centres and the powers they have in their backline," Twelvetrees told Sky Sports News.
"Nothing much changes from our point of view. I think we have got to focus on what we can do as a collective backline and as a team and we are very confident within ourselves of the gameplan we have."