England centre Billy Twelvetrees is primed for his gain-line war with Jamie Roberts after declaring he is expecting the most physical battle he has faced.
"He's a top-class player and he's shown that in the years he has played for Wales and for the Lions. He's always making breaks and getting over the gain line.
The collision between Twelvetrees and Roberts could be seismic - the former is 6'3" and 16 stones, the latter 6'4" and 17 stones.
Wales will launch their 2009 and 2013 Test Lions down the 12 channel at the first available opportunity and Twelvetrees knows the importance of issuing an early statement of intent in defence.
"It's huge for us as a team to get on the front foot straight away," he said.
"Rugby is a huge mental battle and psychologically you want to get on the front foot straight away and get the game going.
"It's the same with Wales, they're going to know what's coming and so will we.
"But you've still got to deal with it. It's about turning up on the day and performing."
Twelvetrees' defence was an area of concern after he was flattened by Matt Toomua in last autumn's victory over Australia as the Wallabies centre forced his way over the whitewash.
"I'm working on it all the time, as the whole team do. It's a huge part of our game. We want to put pressure on attacks and make them make errors," Twelvetrees said.
The Exeter forward has been included in the 23 for the title showdown with Warren Gatland's champions and will feature among the replacements when the team is announced on Friday morning.
A back-row vacancy was created when number eight Billy Vunipola was ruled out of the remainder of the Six Nations with an ankle injury sustained in the 13-10 victory over Ireland.
Ben Morgan will take Vunipola's place in the starting XV with Johnson supplying cover from the bench.
"Tom Johnson has trained with us throughout the Six Nations and we are looking forward to his contribution," England head coach Stuart Lancaster said.
"The performance against Ireland has given us a lot of confidence going into this game against a high quality Welsh team.
Manu Tuilagi will continue to train with England as his club Leicester are not involved in LV= Cup action this weekend, but will not participate against Wales.
The Red Rose will enter the final weekend of the Six Nations with a shot at the title if they dispose of Wales with points difference likely to be the deciding factor.
Centre Billy Twelvetrees insists they have the expectation they will prevail over the champions on home soil.
"Twickenham is the home of English rugby and it means so much to all the boys," Twelvetrees said.
"The Twickenham factor always give you an extra per cent. I can't put a number on it, but it gives you that extra belief and extra bit of energy when you are blowing."
