Since that triumphant day at the Millennium Stadium, he has really been through the mill, both on and off the field.
He endured a difficult Lions tour to New Zealand two summers ago, underwent groin surgery and was then hit with a seven-week ban for elbowing Leicester prop Alex Moreno.
When he did return to action, Henson struggled to rediscover his form and then pulled out of Wales' summer tour to Argentina because he was "not there physically and not there mentally".
But he is now back playing regularly for the Ospreys - albeit at fly-half rather than his Wales position of inside centre - and he is determined to make up for lost time in the Test arena.
He said: "I am glad to be starting. It's massive. It is good to get back playing at the Millennium Stadium and actually starting for Wales again.
"It has been about two years since I started for Wales and I am pretty excited.
"These type of games bring the best out of you. I have been in those situations before. I will probably be a bit nervous this time around because I have not had that much rugby under my belt.
"But I'm glad I got the Stade Francais game under my belt (for the Ospreys in the Heineken Cup last weekend) because it is not too big a step from there to international rugby really."
Henson's inclusion at inside centre was something of a surprise given the early season form of Ospreys team-mate James Hook and Llanelli Scarlets' Gavin Evans.
But he has the backing of new head coach Gareth Jenkins, who said: "We feel as if Gavin has been playing some good rugby and we feel confident and comfortable to give him the opportunity to prove to all of us he can make an impact in that position for us this season.
"He wants the opportunity. There is now serious competition behind him and that is good for all of us."
Henson returns from injury along with fellow Grand Slam heroes Ryan Jones, Kevin Morgan, Gareth Thomas and centre partner Tom Shanklin.
And he believes Wales are a better side now than in their Grand Slam campaign two years ago.
He said: "It will be nice to get the partnership (with Shanklin) back from the Grand Slam days. But that is a long time ago now. We have to build our reputations back up and hopefully we can do that on Saturday.
"I made the decision not to go on the summer tour because I wanted to get refreshed for this season, which is going to be a long one and a good one hopefully.
"I feel I have done that and it is now a case of getting my form on the field and I am not too far away from that.
"My major goal is the World Cup and trying to nail my spot ahead of the other two candidates.
"There is so much competition for places now. This is a stronger squad. That is great from a Wales point of view and great in a World Cup year.
"It is a case of starting now, putting a marker down and hopefully having a successful autumn series."