The stunning reality TV star, 23, admits she was "very shocked" when former TOWIE star and childhood pal Sam launched a fitness website - just months after Lucy had.
Although Lucy kept silent at the time, she has now expressed her disappointment in an interview with The Sun's Fabulous magazine.
Lucy admits she had expected competition from others when it came to launching her career after quitting The Only Way Is Essex – but not from Sam, her childhood friend since the age of 11.
She says: "I haven't seen Sam for I don't know how long, but that's not because we've fallen out. But you know what, she did copy my website, and there's no denying that.
"I came up with a new concept for a fitness website and most things on hers are very, very similar. Mine's just probably a bit more advanced and got a bit more content on it.
"So, yeah, it isn't the nicest thing for a friend to do - someone you've been friends with since you were 11 - I must admit."
Lucy also reveals that Sam had tried to contact her friend about any rivalry, insisting she'd launched her own fitness site because she fell in love with it after her Crohn's diagnosis.
Lucy now says: "I told her that, honestly, I was very, very shocked she'd done it, but that I wished her all the luck in the world.
"We haven't spoken since, but there's been no fallout, and if I bumped into her I hope it wouldn't be awkward."
Lucy, who is dating Olympian Louis Smith, launched her fitness and health website Results With Lucy shortly after leaving TOWIE in December 2013.
As well as the business becoming a huge success, Lucy has starred in BBC1's Tumble and has her own clothing boutique.
She is also on the books of Select Model Management.
Sam, meanwhile, took part in Celebrity Big Brother 2014 but was forced to take a back seat when she was taken ill during filming and was subsequently diagnosed with Crohn's Disease.
As well as her website Celebrity Training With Sam Faiers, she owns Minnie's Boutique with her sister Billie.
Both Sam and Lucy have perfumes and books in their name.
This week, it was announced that Sam is reportedly pregnant with her first child.
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