I'm not doing that, it's too cheesy.

They say everyone has their price, and their limit. I still don't know what my price is but I sure can tell you what my limit is. I walked smack into it yesterday evening, at a casting for a cheese commercial, on the outer edges of West London, zone 2.

When I say cheese, what I mean is processed, squeezed out of a tube, comes in 4 flavours including prawn (I know!) kind of "cheese".

Unfortunately, the commercial (and therefore the casting session) called for a fair bit of eating of the product.

I'm proud to be in recovery from eating disorders but there are still a few things that make me unconfortable and downright loopy. Having to gobble processed cheese is one of them. Having to wait my turn for 45 minutes with the growing realisation that I'm going to have to gobble oodles and oodles of the stuff is another.

By the time I walked into the casting room, I was vibrating with anxiety. Almost levitating with stress. We did the idents (name, agent's name, rigth profile, left profile). Then I got briefed by the director (a woman): You (and before you ask, yes, "you" is another 40 something mum) are digging into the the stuff looking like you're being submerged by waves of flavour and delight.

Come again?

But then again, I am an actor. Surely I can adjust to any request from a director? Taking my clothes off, fine. Appearing with no make-up, fine. Looking unattractive and/or fat, fine. But I'm sorry - I draw the line at eating prawn flavoured anything that you have to squeeze out of a tube.

The director gave me last minute directions (prepare the "canapes", eat, enjoy, look delighted etc...) for the first take and said we'd try something else afterwards.

So I took a big breath and then I fudged it. I ended up eating a few bare pretzel sticks instead of the cheese. My throat was so dry I even struggled with those. I didn't make it past the first take.

I should've felt pretty crushed to be so obviously placed in the "reject" pile, but I couldn't wait to get out of room. Having retrieved my coat and brolly, I fairly skipped out of the building, after a minor freak-out when I accidently walked back into the casting room (through another door) instead of the front door.

I walked back to Kensington Olympia tube station (and it was raining pretty hard) and I felt like a freak. That was the worst bit about the whole experience. I felt different from everyone else: somehow not quite right in the head. All the other women had gone in, done their stuff, and come out wiping their fingers and smacking their lips. And I'd gone in and freaked out (technically, I'd gone in freaked out). Over having to eat some squeezy prawn flavoured cheese.

I know it's fantastic material for my next show.

And now I know what my limit is.