"There are a few of us here but there are also a quite a lot in the Premier League," Simpson told the Leicester Mercury.
"It's extra-special for us to go back and try to put in a performance. It's a bit different as we don't know (manager) Louis van Gaal as it was Sir Alex Ferguson then, so it's good for us to go back and do well.
"For all of us, we can go to Old Trafford full of confidence after last week's win at Tottenham.
"I have played there a few times. There are good memories and I've had some good results going back to Old Trafford.
"Hopefully we can put in a good performance and we can show desire.
"If we can show that again like we did in our last game against them (the 5-3 win in September at the King Power Stadium), then you never know. "
For the big stories and the banter follow us on Twitter: @tribalfootball