It was first suggested that Julian had proposed last week after he hinted during a conference call that he would reveal big news during the show's season finale.
Speaking to Chris Harrison during the final Bachelor Pad episode, Julian called the relationship the "most serious" of his entire life and revealed that Durst would be moving to South Carolina with him so they could be together full time.
A video was then shown of the couple picnicking on a hillside in Los Angeles, where Julian popped the question after presenting Durst with a Neil Lane diamond ring.
"She's everything I've been looking for in some way, from the way she handles situations to her drive and her passion. She's the total package. It's the kind of love that I didn't know was possible. And there's one thing I have to do to show her exactly what I feel about her," he said about Durst.
The development was also news to Durst's final Bachelor Pad partner and ex-fiancé Michael Stagliano, who was openly shocked and emotional.
"I am shocked, so maybe a water would be great or a commercial break would be nice. Congratulations, but seriously, here is where I find out? Even a letter or an e-mail prior... I guess Holly's happy and that's what I wanted for her for the rest of her life, so... it's okay," Stagliano said.
Julian and Durst have not announced when they plan to marry.