Tuesday night's horrow show at Burnley and a week of off-field changes have turned the spotlight on the Reds ahead of their clash with the Blues at the City Ground.
Calling once again for new signings to boost his squad McClaren told the Nottingham Evening Post: "We need to strengthen, we know that. Tuesday (at Burnley) highlighted that. We have put some names forward, we will see what happens."
And, calling on the home fans to play their part he added: "It is important for the fans to be with us. They are our 12th man and we need them.
"I can understand the supporters being angry, but this is an opportunity. We have to stick together and show some fight and spirit. We need everyone behind us, the fans included. If we have not got the result we want at 5pm then, yes, we will deserve everything we get.
"But let's get behind the team, stick together as a club, let's stick together as a team, because we have proved we can do it."
Former Reds striker Marlon King returns to the City Ground and said: “We know Forest are a strong side and won’t be taking them lightly.
“We’ve got to forget that and concentrate on what we are doing.”