The back-row Wasps forward frequently lasted less than an hour in club games last season as he struggled with injury.
Dallaglio, 34, was one of the stars of England's World Cup triumph in Australia four years ago, but had not featured for the national side since the 2006 RBS 6 Nations.
The move was aimed at restoring some experience to the team, which has been on a downward spiral since that victorious night in Sydney.
Wilkinson, 28, kicked the crucial drop-goal to win the World Cup - and maintains his good friend will bring the "attitude" needed if England are to be competitive again in France this Autumn.
"Everybody recognises him from the last World Cup and from rugby in general - but also he is bringing with him the embodiment of an attitude, there is no false face to what he is doing," said Wilkinson.
"Lawrence has come back and he would not be there if he was not 100% behind the fact that he wants to take on this World Cup and show that he has got everything.
"He is one of those players who has achieved so much he does not need that sort of thing.
"Lawrence is there because he believes in the team and massively in himself - that energy is fairly obvious to read and I think that is going to bolster the squad massively.
"He is another voice and a guy that people listen to and his very presence will lift spirits - but also levels of concentration and execution.
"It is great to have him there and I think he will form a big and a loud part of that squad."
Wilkinson was at the Roehampton Club in west London to help launch the Travelex Sport Exchange initiative, which is aimed at giving talented British athletes the chance of first-class training at top venues around the globe.
The Newcastle fly-half has been taking a keen interest in the Tri-Nations series.
New Zealand came from 21-12 behind with 14 minutes left to edge out rivals South Africa in Durban.
Wilkinson feels such performances show the 2007 World Cup will be anything but a one-horse race.
"I think now from watching those first two games in the tri-nations everyone is speaking about New Zealand running away with it - but already they perhaps should have been beaten this weekend," he said.
"Australia should have beaten South Africa, who should have beaten New Zealand, so already we have got three teams messing around with your top ranks for the tournament.
"Then you have got Ireland and France, playing at home.
"You have got us with a brand new set of players who are going to join our squad, and you sort of think there is really only probably one try between the top six teams.
"You have just got to make sure you are on the end of that kick and certainly to one putting the ball down and then you never know where you are going to be."
Wilkinson added: "We have just got to make sure we are there on the day.
"Every outlook is positive going into this tournament. It is a lot of hard work, but we are going to enjoy that challenge."