Eddie Redmayne is ''just trying to keep his children alive''.

The 'Fantastic Beasts: The Crimes of Grindelwald' star loves being a father to Iris, two, and Luke, eight months, and quipped that his main focus is keeping his kids and alive and well.

He said: ''I have two little children -- Iris is now 2 and a half and Luke is 8 months. So honestly, life is about trying to keep the children alive. But they're wonderful.''

And the 36-year-old actor says his eldest child is a ''fantastic'' big sister to Luke.

He added to People magazine: ''She's fantastic. There are occasional moments when Hannah and I are both out of the room and we get a glimpse of Iris entertaining Luke. No one makes him laugh as much as she does. You can't quite believe it. Like, these humans are interacting , so that's been pretty special.''

And Eddie previously confessed he wants a ''sleeping spell'' to get some peace from his children.

Eddie - who is married to Hannah Bagshawe - said: ''I'm promoting 'Fantastic Beasts' so people keep saying, 'What spell would you dream of doing?' I'm like literally just a two-hour sort of sleep spell, people suggest gin but I haven't gotten there yet!''

Meanwhile, the Hollywood star says his sleepless nights are ''totally worth it'' when he sees his daughter's face.

Speaking soon after her birth, he said: ''She is heaven. It's worth it because, occasionally, there's that amazing thing where it's three o'clock in the morning and you go in, and you're sort of gently furious, and then you get a little smile, and your heart breaks a bit, and it's totally worth it.''