Gwyneth Paltrow worries about ''f***ing up'' as a mother.

The 'Iron Man' actress - who has children Apple, 12, and Moses, 10, with ex-husband Chris Martin - finds parenting can be ''tough'' and comes with a lot of pressure because it is such an ''important'' job, and she shares the same fears about raising her kids as so many other mums do.

She said: ''The other night, I was in the bath and I texted my best mom friend, 'Am I f***ing this up?'

''And she was like, 'No! Breathe. We all feel this way, take a step back. Your kids are great.'

''It's tough, but it's the most important thing I do by far.''

The 44-year-old actress admits being a mother is almost like reliving her own childhood but she has to work hard to guide her kids in her own way, rather than just behaving identically to how her own parents did when she was growing up.

She told People magazine: ''It's challenging, rewarding and very emotional. It's like going through childhood again, but standing next to the people that you love more than you've ever loved anybody in the world and helping them bear their heartaches and mistakes and triumphs.

''I think our parents all parented out of instinct and how they were parented, and it takes an incredible amount of energy to divert from that path and be like, 'No, I want to think about this.'

''So not just being reactive and carving out the time to think about how you want to handle something -- how you want to help shape them and help support them.''

The Goop founder is very impressed by her daughter's ''DIY beauty'' tips and regime.

She said: ''Apple is so funny. She's all about DIY beauty. She's so past where I could ever be.

''She makes homemade face and hair masks.

''She makes homemade slime with a gallon of Elmer's glue! That's not a beauty product, but she's very DIY. I don't steal her tips, but I am just on permanent clean-up.''