Lo Bosworth and Heidi

Lauren “Lo” Bosworth says she was surprised to learn that her Hills costars Heidi Montag and Spencer Pratt tied the knot while in Mexico away from family and friends — and after a night of tequila and champagne.

“I always thought they were going to get married,” Bosworth said on The Hills: Live After the Show on Monday. “I just didn’t know when. I thought she always wanted a big, beautiful event wedding in L.A. I was surprised it turned out the way it did actually.”

The Hills star, who said she learned of Montag and Pratt’s nuptials on the Internet “just like everybody else,” also said she was surprised by the alcohol-fueled chain of events. (On The Hills Monday, Pratt suggested he and Montag get married after they’d been drinking. The pair even ordered more tequila while they discussed the idea. “You know what Patron does to me,” Montag said. “It gets me crazy.”)

“She was drunk!” Bosworth said on MTV’s after show. “I don’t know if she was drunk when they actually got married, but the night before she was. She just needed that little push — the Patron push.”

But despite the fact that the two were drinking when they decided to tie the knot, Bosworth said she believes the marriage will last “forever and ever.”