Former A Shot at Love star Tila Tequila had committed to be a Celebrity Rehab cast member early last week, while former Laguna Beach star Jason Wahler was also reportedly "very close" to an agreement to appear on it.
In addition, Bone Thugs-N-Harmony rapper Bizzy Bone -- whose real name is Byron McCane -- expressed interest in participating in it to receive treatment for marijuana and alcohol addiction.
The VH1 reality series was also reportedly interested in casting actress/singer Liza Minnelli and Dutchess of York Sarah Ferguson, however both have denied any involvement in the show.
While Celebrity Rehab would represent Sand's first regular reality role, Lamas is not stranger to it -- as he previously served as a judge on ABC's short-lived 2003 Are You Hot? reality series, competed on Gone Country's second season last summer on CMT, and also stars in E!'s Leave It to Lamas docu-reality series.