What is Christine doing in Japan?

I just watched this movie for the first time. It was on and I was curious because I knew it was Cary Grant's last movie and thought I'd give it a shot. It was entertaining enough...predictable, lightweight fluff. Hardly a classic but decent entertainment and worth watching once or maybe twice.

Anyways, I must have missed this, but what was Samantha Eggar's character doing in Tokyo in the first place? I realize that this detail is hardly essential to the plot but I'm just curious. I might have missed it or perhaps it wasn't even mentioned at all. I was only wondering. The best that I can come up with was that she worked for the British Embassy in some capacity, seeing as how she posted a notice on the billboard. But if anyone caught anything else, I'd love to know. Thanks!