The Royals, who lie sixth in the First Division following their dramatic 2-1 win over Watford on Saturday, unsurprisingly do not hold the position of favourites going into the eagerly-anticipated David V Golliath match-up.
Tickets went first went on sale more than a month ago but with so many people keen to get their hands on their precious match day passes, supporters camped outside the stadium overnight in order to get in.
The game will see only the second ever 24,000+ crowd at the Madejski Stadium.
Chelsea, who spent more than £100m on new signings in the summer, are top of the Premiership following their 1-0 win over Manchester United on Sunday.
Whilst the Blues are likely to field their reserve side tomorrow night, it will be one that contains the likes of Jimmy Floyd Hasselbaink, Neil Sullivan, Joe Cole and Marcel Desially; strong enough to frighten any opposition in the world. (Believe me Thierry Henry, Ruud van Nistelrooy and Ronaldo are frightened by the prospect of coming up against Neil Sullivan).
Reading are advising fans to get to the ground early, and rightly so. Having gone to great lengths to get tickets, no one wants to miss this spectacular. A victory for the Royals is seemingly out of the question such is Claudio Ranieri's commitment to all competitions this season.
However, if the Royals get the Chelsea of yesteryear that could only play in big games, then maybe an implausible win isn't out of the question.
There's not long now.