Both players returned home after suffering injuries in the pool stages but were flown back by the Wallabies for the big game.
Mitchell spoke highly of the “family” ethos that head coach Michael Cheika has instilled in the squad since he took over and how the players chosen for Saturday were desperate to make the whole squad proud.
“It was a really nice surprise this morning when we got down to breakfast and saw big Willy and Cliff down there,” Mitchell said.
“Since Cheik came in, there’s been a real family feel about it. We’ve used a lot of players and some have had a tremendous input throughout this journey that we’re on.
“There are some unfortunate guys who won’t get to pull the jersey on tomorrow. It’s a hard position to be in, to want that so much and be told you’re not going to get that opportunity to play in a final, or even earlier in the pool stages.
“It’s a difficult one but the way these guys have taken it on board and contributed to our preparation has been fantastic.
“It’s now up to us, the guys getting that opportunity to pull on the jersey, to really represent those guys and do something that they can be proud of.”
Mitchell also credited his success with Toulon for helping handle high-profile fixtures in a better way, after making a key break in last week’s semi-final win over Argentina and having scored the decisive try in this year’s European Cup Final – both at Twickenham.
“I’ve got a lot of experience now in tournament-type rugby compared to what I did have after having played for Toulon with the pressures of the pool stages and the elimination games in the European Cup, playing in bigger games,” he added.
“I wasn’t too fortunate throughout my Super Rugby career to play in that sort of environment.
“I’ve gained that sort of knowledge and belief that I can play in those bigger sorts of games and contribute for my team.
“Further than that I’ve got a more rounded view of how the game is played. We’ve got a good mix of international experience throughout the team in Toulon, guys like Bryan [Habana] and from other sides providing insights into how they prepare and handle wins or losses.
“It’s been a tremendous experience for me there.”