For the sake of television ratings and attention, Spencer Pratt pretends to be in love with Heidi Montag.

But a friend tells Star Magazine that the owner of the creepiest, most flesh-colored beard in Hollywood truly is in love with marijuana!

When Pratt was 15, this anonymous source says Spencer started smoking pot and "fell in love with it." The insider added:

"He was smoking it every day. He always had a big bag and would share with everyone. He was the King of Weed!”

Hey, that beats his current nickname: The King of Ass Clowns.

According to an insider, ratings for The Hills aren't the only thing that's high!

Marijuana served as a gateway drug, reportedly, as the friend claims Pratt graduated to Xanax and Valium. In fact, this loyal, totally not made up acquaintance says the first time she ever took Valium was because of Spencer.

"He gave me five [pills] and told me I'd be OK," says the source. "I didn't know it was too much. The next day he said, 'Girl, I gave you so much Valium, and you just handled!'"

Hmmm... that does sound like something Spencer would say.