My night with the stars: Preparing for the Oscars

You don't want to try on too many Oscar dresses prior to actually getting an Oscar nomination. But from the moment I got nominated for Best Picture for An Education in early February, along with my co-producer Finola Dwyer, things started getting really busy.

The moment we heard the news, we jumped up and down, and hugged each other. Obviously we were delighted that Carey Mulligan had been nominated for Best Actress. Then I had to text my husband Nick Hornby, who wrote the screenplay, to let him know he had been nominated. He was far too nervous to watch the live feed online.

We always felt it was a universal story and a star-making role – and we got it right! But it was a difficult film to finance because financiers don't like near period. It is more expensive to make than a contemporary film and it is always harder to market.

It didn't have a starring role for a named actress. It was always going to be a discovery. It has spoken to audiences internationally and we've had the recognition with all the British nominations, and now with the Oscar nominations, it was such an honour.

The first thing we did was get on the phone to a few designers to get hold of a dress. We had just received a very kind and helpful message back from Alexander McQueen's right-hand lady, hours before his death was announced.

I went with the designer Ben de Lisi because he had dressed my friend Christine Langan, when she produced for The Queen. He was willing to work with and adapt a size 12 sample that he had for a forthcoming evening wear range.

It's not easy finding a dress for the Oscars these days. With the economic downturn, people can lend only what they have on the press rails. They can discount what they have in the shops for you quite significantly, but the days of them plucking things off the shop floor and saying "There you go, darling" is not a reality any more.

Of course the press rails are size eight and below. Even though I like to think that Finola and I are in reasonable shape, it's pretty hard to get into anything off the press rails.

We managed to get Adler's jewels for the Baftas, but not for the Oscars. Although previously they had loaned jewels that you could then take over to LA – and they sent security with you to the airport – this year they are not doing that.

We have had to book appointments with Boucheron, a French jewellers, who have an outlet in LA, who I hope are going to be lending us jewels. I may not find something that goes with my turquoise dress. So I had to go and buy pretty cheap but effective costume jewellery from Topshop just in case.

Then I bought a pair of Jimmy Choo shoes to go with my dress but I needed a clutch bag, which was twice as much as the shoes. It would have been a ridiculous purchase as I'd use it only once. But Jimmy Choo can lend you items only in LA from their Oscars range, so I don't know if it will match.

I also bought myself a new Sony Reader and I have been stocking it up with all the reading that I should be doing on the flight going over and on the way back.

Then I just watched a nine-minute DVD that every nominee gets sent from the producers of the Academy Awards. It is fronted by Tom Hanks and it tells you what not to do in your acceptance speech.

I doubt I will need to make an acceptance speech, due to being a very long shot for Best Picture, but it was fascinating to see this year that they've actually asked that only one of multiple nominees is allowed to speak. I would allocate Finola to speak because she is a better public speaker than I am. But there are four writers for In the Loop, so that's a big reduction for them.

They are also desperately trying to discourage people from reading off a list of thanks, thanking everybody from their agent to their dog. Now when you go off stage, you go straight in front of a "thanks cam", which gets loaded on to the Oscar website, and you can forward that link to everybody you have thanked.

I have also been busy dealing with where we are going to sit. Being married to another nominee has posed a really interesting question. Nick would be sitting in the writers' seats and I would be sitting in the producers' seats. But obviously we want to be each other's plus-one, so our director Lone Scherfig and Nick's agent, Jenny Casarotto, are our plus-ones, and they are going to sit as a couple, in whatever seats we are not in.

We will sit in the right seats for Nick's nomination and then we are going to move to the right seats for my nomination. At the moment we don't know how far we will have to move in the auditorium.

We have been told that the academy is quite strict about where everybody sits because the camera people need to have a list of names that match faces.

But Finola knows Peter Jackson and Fran Walsh, who are married and who co-wrote The Lord of the Rings, and of course Peter Jackson was nominated for director, so we emailed them to find out if they had any special arrangement or tips for the husband and wife nominee.

Now the Sony PR people are checking out whether the academy does need to be notified of where we are going to be sitting.

What's nice is that Nick and I are the happy couple story at the Oscars. But there is the divorced Oscar couple story this year, which is Kathryn Bigelow and James Cameron.

What I have been a bit thrown by is the fact that it's not just the Oscar dress you are looking for. There seems to be an event every single night.

I wish I had a beautiful line-up of outfits and matching shoes, but I'm afraid it's going to be a little more mismatched than that. Luckily Finola dropped off a few dresses that we have been loaned by a variety of designers, in case one of them works for one of the other events. My friend Christine Langan, is now coming to the Oscars, in her capacity as creative director of BBC Films and is also hoping to borrow one.

I was partly delighted with my dress because the turquoise went with my colouring, but also because I thought it was easy for my mother to spot me on the red carpet.

The Academy Awards are presented on Sunday night. An Education is released on DVD and Blu-ray on 8 March. Amanda Posey was talking to Charlotte Cripps