Even though France cannot win either prize - the result of a home draw and defeat against Ireland and England, respectively - they could still gatecrash Wales' planned Millennium Stadium party.
And history is also on Les Bleus' side, having won five previous Six Nations Tests and lost only one - the last time Wales were crowned Grand Slam champions four years ago - in Cardiff.
"The pressure is on us, we are at home, and France will probably want to come here and spoil the party," said former Wales captain and current hooker Rees, who wins his 50th cap on Saturday.
"We have to make sure we deliver on the day.
"The changes France have made up-front, they are definitely going to try to come here and bully us. That is one thing we have got to be mindful of.
"They have picked a front-five to try to irritate us and see how we respond to that.
"One team that tries to bully you is South Africa, but as far as I am concerned whenever we have played at home I don't think there is any team that has come out on top.
"As a pack, we've got plenty of experience and hunger there. We are relishing the challenge."
Victory for Wales on Saturday would not only confirm them as European champions, it would also underline the consistency coach Warren Gatland is striving for five months after securing a World Cup semi-final place in New Zealand.
Seven of this weekend's starting line-up are aged 24 or under, and Rees, who made his comeback from injury against Italy six days ago, is enthused by what Wales could go on to achieve.
After the Six Nations campaign is over, they face a three-Test summer tour to Australia, while their Millennium Stadium opponents next November include World Cup holders New Zealand.
"You can't underestimate how big the World Cup was for us as a nation, and after it we were always going to be favourites to win this Six Nations," Rees said.
"In the past, we have always come in as underdogs, but I think this group of players have taken us to the next level.
"Our fitness has gone to another level, which has been great for us in terms of the way we want to play the game, because we are coming through strong at the end of games.
"We have got a lot of young boys in the team who are going to be around a lot longer than the senior guys.
"The biggest thing for me is we've come a long way in the last 18 months, and the important thing now is we don't get carried away and keep on building.
"It was always the big question mark. We'd had a great World Cup, but could we continue with that in the Six Nations? The boys have delivered it and it is important we grow again from here.
"It is impressive what the younger guys are doing. George North is a rare breed. We all thought we would struggle when Shane (Williams) retired, but we've got George and Alex Cuthbert on the scene, which is great for us.
"We know how great a player Shane has been, and for the likes of George and Alex to step in can only be good for us. There is a lot of competition in the squad which drives players on."
For Rees, if Wales match the achievement of the 1970s golden era teams by capturing three Grand Slams in eight seasons, it would represent a triumphant return from the lows of last year when a neck injury meant he missed the World Cup.
"After missing out on the World Cup and the opening Six Nations games, to get the 50th cap is a great achievement for myself," he said.
"We are at home, going for the Grand Slam in front of a full house. You couldn't ask for a better game to be involved in.
"Back last year, before the World Cup, the neck injury was a bit of a concern, but after seeing the surgeon I was happy there were not going to be any issues after the operation and I would come back playing.
"As much as it was all doom and gloom at the beginning, I could see light at the end of the tunnel."
Wales: L Halfpenny (Cardiff Blues); A Cuthbert (Cardiff Blues), J Davies (Scarlets), J Roberts (Cardiff Blues), G North (Scarlets); R Priestland (Scarlets), M Phillips (Bayonne); G Jenkins (Cardiff Blues), M Rees (Scarlets), A Jones (Ospreys), A-W Jones (Ospreys), I Evans (Ospreys), D Lydiate (Newport Gwent Dragons), S Warburton (Cardiff Blues, capt), T Faletau (Newport Gwent Dragons)
Replacements: K Owens (Scarlets), P James (Ospreys), L Charteris (Newport Gwent Dragons), R Jones (Ospreys), L Williams (Cardiff Blues), J Hook (Perpignan), S Williams (Scarlets)
France: C Poitrenaud (Toulouse); W Fofana (Clermont Auvergne), A Rougerie (Clermont Auvergne), F Fritz (Toulouse), A Palisson (Toulon); L Beauxis (Stade Francais), D Yachvili (Biarritz); J-B Poux (Toulouse), W Servat (Toulouse), D Attoub (Stade Francais), P Pape (Stade Francais), Y Maestri (Toulouse), T Dusautoir (Toulouse, capt), J Bonnaire (Clermont Auvergne), I Harinordoquy (Biarritz)
Replacements: D Szarzewski (Stade Francais), V Debaty (Clermont Auvergne), J Pierre (Clermont Auvergne), L Picamoles (Toulouse), M Parra (Clermont), F Trinh-Duc