Alan Sidney Patrick Rickman was born on February 21 1946 on a council estate in Acton, west London. “My mother was Welsh and my father was Irish and I can speak both accents like a native, yet in my whole career I have never been asked to,” he later recalled.
Now there’s the beginning of a plot idea.
So, twins, adopted out, one brought up in Wales, one in Ireland……now adult. Both played by Rickman, obviously. Take it from there….