Saber: Bedivere, I'm pregnant.
Sir Bedivere: Congratulations, my K... Wait! I apologise my King but... What?!
Saber: ... Please, go and return Excalibur to the Lake.
Sir Bedivere: ... Y-Yes.
People never knew how Sir Bedivere ended up with that red haired kid.
And, that's what they meant with "The Once and Future King".