The "Homeland" actress says she bowed out of consideration for the Oscar-winning blockbuster, letting the lead role ultimately go to actress Kate Winslet back in 1996, largely because the part felt all too familiar.
Danes had just wrapped Baz Luhrmann's "Romeo + Juliet" with DiCaprio, and was looking for a different type of venture, reports aceshowbiz.com.
"I had just made this romantic epic with Leo in Mexico City, which is where they were going to shoot 'Titanic'! And I just didn't have it in me!" Danes said during a sit down with Dax Shepard's Armchair Expert podcast.
The 40-year-old recalls DiCaprio himself wrestling with the decision to take on the James Cameron epic, recounting a conversation they had outside their mutual manager's office.
"And he just looked up at me and said: 'I'm doing it! I'm doing it!' And I could see he wasn't sure. But he was like, 'F**k it, I gotta do this thing.'"
Danes added that she could not see herself grappling with the global attention the actor received following the film's release.
"And I looked down at him, and I was like, 'I totally understand why you're doing that. And I'm not ready for that.' And I think I really wasn't ready for it. And I remember after that movie came out... and he just went into another stratosphere."
She noted she has "zero regret" after noticing a swift change in how people treat her former co-star.
"I think I may have sensed that I was courting that (level of fame) or I was proximate to that... and I just couldn't do it. I didn't want it. I was just really clear about it. I wasn't conflicted," she said.
As for whether or not anything romantic happened between the pair while they were filming the classic Shakespearean love story, she believes off-screen love was not written in the stars for them.
"That was just never going to happen," she said, while admitting there was a "crushy" vibe between the two.
"I didn't know how to go about that... we're really different people."
( With inputs from IANS )