The actress, who lives in London, has spoken out about how the role negatively impacted her real life.
Lily used method acting to get herself ready to become the 1990s icon but claims this led to poor mental health.
She told The Mirror: “It was such a screwed-up process. You have to be patient with yourself. The hours are so long and you feel really burnt out.
“Your nervous system is just like, shot to s**t. I felt like a real wreck at the end of it.”
Lily went on to say that she stayed in character so much that she spoke to her mother in the voice of Pamela and even wore her giant blonde wig in real life.
Lily said: “Even when I went out for dinner and was ordering with the waitress or talking to my mum on the phone, I would be American.
“I think I’ve lost lots of jobs because I keep speaking like Pamela in auditions.”
Lily was committed to mirroring Pamela, so much so that she memorised all of her interviews and underwent an intense physical transformation for the role.
She told Gold Derby: “I had a prosthetic forehead, I had teeth, I had contact lenses, I had hair, I had boobs.
“It was so freeing to look in the mirror and see someone else. All through that four hours in the morning I would watch videos of her.
“She speaks really fast so I would have vocal exercises. It would take four hours for me to spiritually and physically get there.”
Pam and Tommy was released on 2 February 2022 and follows the aftermath of a sex tape leak in the 90s.
Lily James plays Pamela Anderson, who is best known for being on Baywatch, and Tommy Lee - a drummer from the band Motley Crue.
The TV show follows the real life events in which the couple’s sex tape is leaked and causes major consequences for the celebrities involved.
The series is still available to watch on streaming service Disney Plus.
Lily received an Emmy nomination for her portrayal of Pamela, but the award went to Amanda Seyfried who played Elizabeth Holmes in The Dropout.