It has been claimed that the actress" relationship with Mendes, 44, suffered on set and eventually led to their break-up. The couple separated several months ago and made the split official on Monday. However, DiCaprio has become a shoulder to cry on as cracks appeared in her six-year marriage.
"Leo and Kate have been like brother and sister since they starred in Titanic together," the Sun quoted a source as saying. "And since Kate's marriage started to go south, around the time they were filming Revolutionary Road, they've got closer again. Kate has always really adored Leo and feels like she can tell him anything."
"They were so young when Titanic came out, so it's fair to say they basically grew up together, professionally at least. They were thrust into stardom together and were the only people who knew what the other was going through. He's been a rock for her," the source added.