Years ago I watched a film where an alien and human are having a dogfight (each in their own small spaceships). They crashland on a planet together, and although they still want to kill each other, they realise they can't survive without each other's help. (They don't share a language.)
In the end
the human helps the alien give birth by cutting her open.
The film starts with what you think is a sun rising over a distant planet, and the planet turns out to be a dead astronaut's helmet.