Johnny Flynn, who plays the young Albert Einstein, was born on Albert Einstein's 104th birthday (March 14, 1983).
This is the first ever scripted drama produced on the National Geographic channel.
Samantha Colley bears a striking resemblance to the real-life Mileva Maric, as can be seen through photographic comparisons.
As they were playing the same character in different timelines, Geoffrey Rush and Johnny Flynn naturally didn't share any scenes together. But they did do several workshops together in which they made sure that the character's gait and vocal mannerisms were the same throughout. This wasn't an entirely new process for Rush as he had done the same with Noah Taylor when they made Shine (1996) 21 years earlier.
Johnny Flynn dyed his hair black, wore brown contact lenses and also sported some minor prosthetics to turn him into the young Albert Einstein.