But I can't for the life of me think who. Some American actress, but that's as far as my brain goes.

Any suggestions?

It's not an American actress, but she reminds me a lot of Emma Walker from the first series of Young Apprentice. She looks and acts in a similar way, and they both sell eggs.

She seems quite horrible so far.

A Middleton sister

I wouldn't know one of the Middletons if they farted on me, so it's not them.

Ah, I think it just clicked. Carrie-Anne Moss.