Cameron Diaz taught Gwyneth Paltrow to blow dry her hair.
The 43-year-old actress - who wrote 'The Longevity Book' on ageing gracefully - has admitted she had to take the 'Iron Man' star through a step-by-step guide on "blowing out" her golden locks.
Speaking on Sirius XM's Radio show 'Andy', hosted by Andy Cohen, about the 'Goop' founder's lack of cosmetic knowledge, she said: "Honestly, I look at her [Gwyneth] and I know what she does, and I know how well she takes care of herself and everybody around her.
"She's so loving and giving and generous to everybody around her, but she was like, 'I never blew out my hair, like, I don't know how to do my own hair and make-up,' and I was like, 'Girl, after all these years, you have to know how to do this, you know?'
"So I showed her how to do a quick blow out on her own hair, and she was like, 'That's it?' I was like, 'That's it.' She's like, 'I can do that!' I was like, 'Of course you can! It's easy, because we have all these other jobs that we have to do that we leave that to other people, but it's really not that difficult to do yourself.'"
However, Gwyneth previously admitted the blonde beauty's husband Benji Madden has always been her beauty muse.
Speaking previously to Elle Magazine about who inspires her make-up, the mother-of-two said: "Cameron Diaz is probably my biggest beauty mentor of my friends. She knows how to do her own hair and make-up."