After their so-called elopement last week, "The Hills" actors Heidi Montag and Spencer Pratt's "surprise wedding" may possibly be just another one of their ploys to extend their 15 minutes of fame.

It has been learned that the couple - who are given the public moniker Speidi - didn't have a legal wedding in their Cabo San Lucas, Mexico wedding last Thursday.

Kim Kardashian is to appear on "How I Met Your Mother." The socialite will be joined by "The Hills" stars Spencer Pratt and Heidi Montag in an episode of the sitcom in which they will play "magazine cover versions of themselves," a show source has confirmed.

Kim - who shot to fame alongside her family in reality TV program "Keeping Up With the Kardashians" - says she can't wait to appear on the show because she is a massive fan.