True story or Cold War myth?

I remember hearing a story about a western spy (possibly American) who went under cover in the Soviet Union sometime towards the end of the Cold War. He’d persuaded everybody he was Russian, but then one day he was invited to a meal, and held the fork in his right hand to eat chips, something a Russian would never do. This gave away his true identity and he was killed.

I was just wondering today whether this is a true story, and what that spy’s name was. Or is it just one of the many urban legends that pop into existance every now and then?