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Lauren Conrad was invited to Heidi Montag and Spencer Pratt's weekend wedding, but she's not going.

Maybe you can.

"My ticket is currently on eBay, so...." she joked to David Letterman Thursday night.

Look back at Heidi and Spencer's romantic wedding in Mexico.

The designer -- who ended her run on The Hills earlier this year -- says she won't sue Pratt for starting rumors that she starred in a sex tape. The lie ruined her friendship with Montag, who sided with her soon-to-be husband.

See all of Lauren Conrad's many BFFs.

"He would enjoy the publicity," Conrad says.

Letterman admitted he was bummed the tape was a fake. "Sorry, I kind of wanted to see it," he told Conrad.

Look back on celeb scandals.

The Late Night host also called Pratt "creepy."

"The beard doesn't help," Conrad said.

"He's not super nice," she continued.