The Transformers beauty likened Lohan to the tragic icon as she talked about removing a Monroe tattoo from her arm, admitting she didn't want to be reminded of the late actress' shortcomings.
She told Esquire magazine: "I didn't want to visualise something so negative... She (Monroe) wasn't powerful at the time. She was sort of like Lindsay. She was an actress who wasn't reliable, who almost wasn't insurable... She had all the potential in the world, and it was squandered. I'm not interested in following in those footsteps."
The remarks were seen by some as a harsh critique of Lohan, but Fox is adamant she was trying to make a "factual comparison" and did not intend to offend.
In an open letter posted on her Facebook page, she writes: "In the newly released article that I did for Esquire, there is a reference that is made to Lindsay Lohan that I would like to clarify before it snowballs into something silly.
"The journalist and I were discussing why I was removing my Marilyn Monroe tattoo, especially since, in his opinion, Marilyn was such a powerful and iconic figure for women. I attempted to draw parallels between Lindsay and Marilyn in order to illustrate my point that while Marilyn may be an icon now, sadly she was not respected and taken seriously while she was still living.
"Both women were gifted actresses, whose natural talent was lost amongst the chaos and incessant media scrutiny surrounding their lifestyles and their difficulties adhering to studio schedules etc.
"I intended for this to be a factual comparison of two women with similar experiences in Hollywood. Unfortunately it turned into me offering up what is really much more of an uneducated opinion. It was most definitely not my intention to criticise or degrade Lindsay. I would never want her to feel bullied, as she does not deserve that. I was not always speaking eloquently during this interview and this miscommunication is my fault."
Lohan worked with Fox on 2004 teen movie Confessions of a Teenage Drama Queen, and she also has her own tattoo tributes to Monroe.