The former King of Queens star hit headlines last week (ends30Oct15) when she opened up about her exit from the Church of Scientology in 2013 during a candid interview on U.S. news show 20/20, and detailed accusations allegedly made against her by Holmes and her then-husband Cruise after she attended their wedding in Italy in 2006.
Remini claims the Batman Begins actress was among a number of Scientologists who filed complaints, known as "knowledge reports", about her alleged behaviour during the extravagant nuptials, and she was later chastised by organisation officials for "ruining" the "wedding of the century".
A preview of the interview aired on U.S. breakfast show Good Morning America on Friday (30Oct15), and hours later, a representative for Holmes, who left the church after splitting from Cruise in 2012, issued a brief statement, which read: "I regret having upset Leah in the past and wish her only the best in the future."
Remini has now spoken out about the apology in a follow-up interview with Good Morning America on Monday (02Nov15), when she admitted the pain she felt during the alleged feud was likely nothing compared to the struggle Holmes had secretly been fighting during her high-profile marriage.
Fighting back tears, Remini said, "It almost makes me want to cry. It makes me emotional because at the time that Katie and this particular crew were writing reports, it caused me a lot of time and pain in my family... So at the time I was fighting with her - I guess for the lack of the better word - within the church, and now I know really what she was going through."
The TV star, who recounts her experiences in her new memoir, Troublemaker: Surviving Hollywood and Scientology, believes both actresses decided to cut ties with the church for the sake of their daughters, and she is thankful they can now be "human" again.
She continued, "Looking back now and seeing her and (daughter) Suri out there in the world and her being able to be with her daughter and live her life, I'm touched by it, because I know now she did what she did, leaving (Scientology) in the way that she did, because she had to protect her daughter, which in a way connects us now...
"It's really because we both left that we're able to have this kind of grace towards each other. Because we're back to being human."
Holmes has never spoken out about her experiences with Scientology or her ex-husband's longtime involvement in the church.