Asked by PEOPLE if there is anything Conrad, 21, could do to patch up their onetime friendship, Montag, 20, bluntly replies: "No, I don't think so."
The pair found fame last year on MTV's Laguna Beach spinoff, which also managed to chronicle how they became bitter enemies. The beginning of the end came in Season 2 when Montag began dating Spencer Pratt.
Speaking to PEOPLE on Wednesday during the Hills's Season 3 premiere party at the LG House in Malibu, Montag attended with Pratt, her fiancé and music manager.
"I have my life and she has hers and I'm honestly so busy with music that I don't have time for a feud," she says.
And according to Montag, living with Pratt beats sharing a pad with Conrad.
"It's way better. You don't have all that catty girl bickering," says Montag. "It's calmer, nicer. We are on the same agenda, you know? So it is like our days are the same."
Such is the bitterness between the girls that Montag has a single word reply when asked if she has any good memories of Conrad: "No."
"[I'm] just moving on. Moving forward. My life is the best now it has ever been so that is all I'm thinking about," she says.
For all the acid among the former friends, Montag does at least offer a small olive branch in the direction of Conrad.
"If she really came around I'd always be open to talk to her," says Montag.
Andrew Shawaf / Pacific Coast News
Less than six months ago Conrad was insisting that she was still friends with Montag. But when Brody Jenner, whom she dated briefly last year, made unflattering remarks in Details alongside his pal Pratt, Conrad laid the blame on Montag's man.
"Honestly, I was nauseous reading it," Conrad said. "I do feel a little bad because if you read almost every quote, it's Spencer. [Brody's] a better person without Spencer."
Conrad's other ex Jason Wahler was also at the premiere event and told PEOPLE he's "sick" of the battle against his former flame. Earlier in the day, he had gone as far as saying he'd take a public lie detector test regarding the sex tape rumors Pratt has been peddling.
"It's been going on for like two months now. I'm over it," Wahler said.
Pratt seemed less inclined to submit to the test when asked about it by PEOPLE, he responded, "It's their lives. No comment."
Reporting by SHAYNA ROSE ARNOLD