"They've spoken over the last few weeks," a confidante told Us of Holmes, 33, and Kidman, 45. "Nicole has been supportive, saying she's been through it too and to hang in there."
After nearly 11 years together -- and kids Isabella, 19, and Connor, 17 -- Cruise, 50, and Kidman divorced in 2001.To better understand what kind of insight Kidman may have offered Holmes, Us recaps Kidman's own memories about her 11-year union with Cruise.
The Days of Thunder costars married in December 1990, and the Australian actress gushed to the BBC, "I was lucky at 22 that I met somebody who fascinated me, amazed me, who could keep me interested." She explained, "I walked in [to the Days of Thunder audition] and [Tom] was the one that stood up and shook my hand. And I just remember...electricity going through me."
But Cruise's super-sized fame was difficult for Kidman to accept at times.
"I became famous very young," she told Marie Claire in March 2011. "I became very famous because I was the wife of somebody."
"I felt I became a star only by association. I didn't think (my early movies) were very good, which is why I would always cower in the background," the actress confessed. "I thought, I don't deserve to be here. We would go to the Oscars and I would think, I'm here to support him. I felt it was my job to put on a beautiful dress and to be seen and not heard."
Kidman had hoped, however, that their high-wattage life would settled down. She explained, "I knew he was a really big star, but after a while, to get to a real place in a relationship, that has to wear off."
"He was huge; still is," the Moulin Rouge! actress told Ladies' Home Journal in June 2006. "To me, he was just Tom, but to everybody else, he is huge. But he was lovely to me. And I loved him. I still love him."
The couple adopted daughter Isabella, now 19, in 1992 and son Connor, now 17, in 1995.
"From the minute Tom and I were married, I wanted to have babies," Kidman told to Vanity Fair in 2007, revealed an earlier miscarriage. "And we lost a baby early on, so that was really very traumatic."
The couple divorced in August 2001, and the actress told Elle magazine in 2008, "I don't want to take away from 11 years with that man that were really important. Really, for our kids -- they were amidst a lot of love. It wasn't bad. And now we're amidst a more evolved love."
Kidman married country singer Keith Urban in June 2006 and they have two daughters together: Sunday Rose, 3, and Faith Margaret, 17 months.
Despite being happily married now, Kidman admits her divorce from Cruise was very difficult to get through.
"I was really damaged and not sure whether [love and marriage] was ever going to happen again to me," she told Marie Claire.
For those eager for nitty-gritty details on the ups and downs of the romance, however, Kidman is staying mum. "I want to honor that marriage for what it was, and there is nothing I would go into about that, she told British GQ in 2009. "I have never discussed the intricacies of it and I never will."
Still, she did joke with David Letterman in July 2001, "I can wear heels now."