Gwyneth Paltrow feels a "deep sense of impending grief" about her children heading to college

The lifestyle guru admits she has no idea what life will look like once her children fly the nest because motherhood has been her whole identity and "guiding force" for the past two decades.

Moses and Brody are heading to university later this year.

She told The Australian Women's Weekly magazine: "It'll be interesting to see how the morning routine changes with no kids in the house."

Asked how she feels about them flying the nest, she confessed: "On the one hand incredible sadness.

A deep sense of impending grief.

"On the other hand this is exactly what should be happening. Your kids are supposed to be, you know, young adults who can achieve and cope and make connections and be resilient.

That's exactly what you want. And that means they leave the house." So it's complicated? "Yeah. I've been so defined and so fulfilled by motherhood. It's been kind of the central... it's been like the central kind of... I don't know even how to articulate it! It's like the guiding force. It's what I return to."

Gwyneth hopes to find the "silver linings" and is "excited" to see how her life will change and what she will get up to without her brood at home.

The 'Iron Man' star added: "I'll let you know. I was talking about this with a friend of mine the other day. As a woman I think we have these very distinct chapters, and you have no idea what these life changes are going to feel like until they happen, right? You don't know what it feels like to be married until you're married. You don't know what it feels like to lose a parent until you lose a parent. It's like you get a whole new lexicon of feelings and I don't know what it's going to be, but I'm going to try to stay really open, try to find, I don't know, the silver linings."