X17 EXCLUSIVE - Heidi Montag Joins Celebrity Rehab Season 5

Heidi Montag has officially signed on to season five of Dr. Drew's Celebrity Rehab, X17online has learned exclusively.

While it was reported the reality star was in talks to appear on the show for her addiction to pain pills, Montag was taken to the sober house two days ago to begin the 21-day rehab program.

A source close to the situation tells X17online exclusively:

"Heidi was dropped off at the house two days ago by a friend, not Spencer. She is going to be on season five with the rest of the cast, but they were going to make her share a room with DC Housewife Michaele Salahi, and she threw a huge fit about it. Heidi had an absolute meltdown and was taken out of the room she had to share. There was major drama going down about where Heidi has to stay, and show producers had to switch up the room assignments just to accommodate her."

No wonder there's drama.

Montag will join just-announced cast members: New York Mets pitching great Dwight "Doc" Gooden, Real Housewives of D.C's Tareq and Michaele Salahi, actress Bai Ling, Michael Lohan, and Baywatch star Jeremy Jackson.

Sounds like one heck of a season for Celebrity Rehab!