The Wales coach has opted to recall rising star Hook at fly half for the Grand Slam clash against France on Saturday. And Gatland insists it was his toughest call since becoming national boss last December.
“Telling a player he is out of the team is always a hugely difficult part of the job of any coach,” he said. “It’s tough on us to make that call and Stephen is absolutely gutted and disappointed – I felt for him.
“But just like in every game, we have looked at the number 10 situation. We’ve gone for a more attacking option in James who will be more of a threat to France.
“That’s no consolation to Stephen but he has the experience and maturity should we need to change the game or close it out in the final minutes.”
Wales will lift the title and clinch their second Grand Slam and championship in four years if they avoid a 20-point defeat by Les Bleus. But Gatland is wary about this weekend’s opposition who themselves are chasing a third successive Six Nations title in Cardiff.
“We’ve got a poor record against France at the Millennium Stadium. They have been the best team consistently in the Six Nations and have won back-to-back championships as well as two Grand Slams in 2002 and 2004.
“It looks like their experiment on team selection is over and they have picked an experienced team with pace, power and big backs. We know it will be a real challenge for us.”
Hook will partner Croke Park yellow card victim Mike Phillips at half back and is one of only two changes with Huw Bennett recovering from a bout of flu to take over at hooker from Matthew Rees.
Second-rower Ian Gough, 31, will lead out Wales at the Millennium Stadium on the occasion of his 50th cap.
Wales: L Byrne; M Jones, T Shanklin, G Henson, S Williams; J Hook, M Phillips; G Jenkins, H Bennett, A Jones; I Gough, AW Jones, J Thomas, M Williams, R Jones (Capt)
Replacements: D Jones, M Rees, I Evans, G Delve, D Peel, S Jones, S Parker