HEIDI MONTAG AND SPENCER PRATT ELOPE

Introducing, Mrs. Heidi Montag Pratt! The Hills star wed her longtime beau, Spencer Pratt, in a secret ceremony in Cabo San Lucas, Mexico, on Nov. 20, Us Weekly reports in its newest issue. See exclusive photos wedding photos in Us Weekly's new issue, on stands now.

"The minute we said our vows, I couldn't stop crying," Montag, 22, tells Us. At the altar, Pratt, 25, told his bride: "Heidi, from the moment you came into my life, I knew my life would never be the same without you. You are the light in my life like the sun to the earth! Your loving warmth makes me want to be a better person. Being with you, I feel complete. I'm honored to even be able to call you my wife. You are the most amazing, loving and caring woman on this planet. I will love you forever and always."

Someone who might not be so thrilled? Montag’s mother. "I called her right before the ceremony, sort of hinted that something that happened, but her reaction was to ask me if we were breaking up! I told her it might be something else, and she said, 'Well, if you ever plan on getting married just know that your stepdad is really upset that you want your father to walk you down the aisle,'" Montag tells Us. "She was starting so much drama, it kind of pushed me toward wanting to get married without that," she adds. "I don't know when I'll tell her."

Pratt and Montag have had a tumultuous relationship. In 2007, Pratt popped the question (after just eight months of dating) with a diamond-encrusted platinum band set with a purple stone that he'd purchased from the mall. But after bickering over Pratt hitting on women in a club, the pair took a "relationship vacation" just a few months later. "I'd just turned 21, and it was scary because I was so young," Montag told Us following the split. (What happened to the bling? "I turned it into a pendant," Montag told Us in December. "It wasn't my dream ring. I don't like what it represents. I might sell it.")

The pair gave it another go in May 2008, after a secret make-or-break getaway to Mexico where "Heidi read me biblical passages like 'Honor thy wife,'" Pratt explained. By the end, he'd convinced her to plan their wedding again. "I'm ready to marry Spencer," Montag told Us that month. "He's my soulmate." Montag was BFFs with Lauren Conrad until early 2007, when Pratt urged Montag to move out of Conrad's apartment and in with him.

For all the details on Pratt and Montag's romantic wedding, pick up the newest issue of Us Weekly.