Based on past excerpts, Naya Rivera's memoir Sorry Not Sorry: Dreams, Mistakes and Growing Up -- which hits shelves today, September 13 -- offers a revealing and candid look at the actress’s life. And a significant part of that revelation includes details regarding her purported feud with former Glee co-star Lea Michele.

In her book, Rivera explains the rift between her and Michele, hinting that their comparably competitive natures ultimately made for a poor fit in regards to both their personal and professional relationships with each other.

"One of the Glee writers once said that Lea and I were like two sides of the same battery and that about sums us up," Rivera wrote. "We are both strong willed and competitive — not just with each other but with everyone — and that’s not a good mixture.”

Rivera continued, inferring her character Santana's increased involvement in the show bothered Michele.

"As the show progressed, though, that friendship started to break down, especially as Santana moved from a background character to one with bigger plot lines and more screen time," the Devious Maids actress wrote. "I think Rachel — erm, I mean Lea — didn’t like sharing the spotlight. On top of that, she had a hard time separating work from our outside friendship, whereas it was a lot easier for me."

Rivera also claims Michele was overly sensitive on set, which led to flared tempers.

"I’m not offended when people offer feedback or criticism, and if things get heated on set, I try to keep perspective. We’re all stressed, yes, but we’re all working toward the same goal, so laugh it off and keep it movin," she wrote. "Lea was a lot more sensitive, though, and it seemed like she blamed me for anything and everything that went wrong.”

Still, while Rivera maintains the two will likely never be friends again, she says their disagreements were overblown by the media.

“If I’d complained about anyone or anything, she’d assumed I was b---tching about her,” Rivera continued. “Soon, she started to ignore me, and eventually it got to the point where she didn’t say a word to me for all of season six. Lea and I definitely weren’t the best of friends, and I doubt we’ll ever sit on her couch and eat kale together again, but the rumors of our ‘feud’ were blown out of proportion.”

Read the full excerpt from Sorry Not Sorry via Twitter below.

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