Is Harold Zidler (Moulin Rouge) Satine's father?

Just something I was wondering... I always thought perhaps they were related, considering the nicknames he calls her and the true caring attitude he has towards her. He calls her "liebchen", "my little sparrow", "sweet strawberry", etc... and she says "all my life you made me believe"... etc. And today I was rewatching it and he says to her "would Daddy let you down?" ... so yeah... I'm confused. xD