Some of the best tennis I have witnessed in the last few years has been when these two have met and I really feel this could be the match of the tournament.
The first time they met, in Australia in 2007, it was a breathtaking five set match - I've rarely seen either player play as well.
Nadal won the first five meetings between the pair, but Andy has won three of the last five, and probably played his best ever match against Nadal to beat him at the Australian Open this year.
Okay, Nadal was injured in the third set, but I don't think he was that hurt in the first two sets, and the first set was some of the most breathtaking stuff I have ever seen on a tennis court.
Rafa just seems to bring out the best in Andy, and I think Andy brings out the best in Rafa too.
It is the match everybody around Wimbledon has been talking about. Amongst the ex-players and commentators I would have said 48 hours ago that about 65 per cent of them were predicting Nadal to win, but I've since noticed a shift, and now it is about 55 per cent in Nadal's favour with that number closing all the time.
Looking at the two respective gameplans that the players might employ and I don't think Nadal has to do anything drastically different to cope with Murray.
He will just look to do what he always does - try and dictate things from the baseline.
Serving well will be important too, and there is always a question about whether his knees will hold up, especially as this is unlikely to be a quick one.
However, there can be absolutely no question marks about his temperament; he is unrivalled amongst today's players in that department, he is more than willing to keep slogging away all day.
I think for Murray to win, he has to avoid playing a passive game. If it comes down to them just battling it out at the baseline then Nadal is going to win.
Murray needs to serve very well and be aggressive. When I say aggressive, I don't mean he should be looking for winners every shot, but he needs to be patient and then take his chances, because against Nadal he won't get too many of them. It is all about getting the percentages right.
I know he rates Nadal more than anyone else, including Roger Federer, and it all points to a fabulous contest.
It is going to be very noisy out there, Nadal has a lot of followers at Wimbledon, especially amongst the younger fans who seem to really relate to him, but I think the vast majority will be cheering on Murray.
Novak Djokovic is a law onto himself... and he now looks completely unrecognisable from the player who started this tournament.
He was pretty dreadful to be honest in his first round match with Olivier Rochus, and if you said at that stage that he would have a big chance of reaching the final, well then you would have been calling for the men with the white coats.
However, he is playing much better now, his serve in particular has improved, and he has made himself a big proposition in this tournament.
Nevertheless, I see the outcome of his semi-final with Tomas Berdych more coming down to how Berdych copes with the occasion.
If the Czech player doesn't get nervous then I think he can do it.
I thought he might get a little shaky against Federer but he held it together really well; he has a huge game, the conditions are perfect for him, and I think he has a big shot of making the final.
There were no surprises in the women's semi-finals but I must say I was hugely impressed with the way Vera Zvonareva recovered from a set down to beat Tsvetana Pironkova and reach the final.
It had looked as if Pironkova was continuing from where she left off against Venus, but Zvonareva turned it around with a huge performance.
In the past, Zvonareva has not been able to take it mentally when she has not been playing well. The tears would start to flow and the bottom would go out of her world, but she really stayed focused against Pironkova which put her in the prefect position to capitalise when the Bulgarian's forehand went a little off.
Those demons of hers seem to be a thing of the past, she has also been unlucky with injuries, especially with her wrist, but she seems to have knuckled down, put those things behind her - so fair play to her.
She has a chance against Serena Williams in the final, but only a small one I feel.
Serena has just looked more and more impressive as the tournament has gone on. At times this season she has struggled to close out matches but against Petra Kvitova she looked every bit the champion she is in the second set.
An upset in the final looks very unlikely. Serena is just such a towering presence and almost unplayable when in form.