The 72-year-old lifestyle guru has blasted the 41-year-old actress and her lifestyle website, Goop.
Talking to Net-a-Porter's Porter magazine, Martha said: ''[Gwyneth] just needs to be quiet. She's a movie star.
''If she were confident in her acting, she wouldn't be trying to be Martha Stewart.''
It is not the first actress-turned-lifestyle guru that Martha has blasted.
Recently, when speaking about Blake Lively's lifestyle blog and brand, Preserve, Martha said: ''Let her try. I don't mean that facetiously! I mean, it's stupid, she could be an actress!
''Why would you want to be me if you could be an actress? I just did a movie yesterday, though - I can't even tell you about it - but I want to be Blake Lively.''
Despite the verbal bashing from her pal Martha, the 'Gossip Girl' star was happy to stand up for the television personality and 'Iron Man' actress, explaining that their work allowed other women to get involved in lifestyle websites and blogs.
She said: ''I'm always the first person to defend Gwyneth Paltrow.
''Or any woman in a position of power, like Martha Stewart or Oprah, who gets burned because they have paved the path for so many other women who are doing something they believe in.''
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