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John Rubinstein is an American actor, composer, singer and director.  On House, M.D., he portrayed Dr. Ayersman, the transplant surgeon in the Season 2 episode The Mistake.

Rubinstein has over 170 television and movie credits including featured roles in Family, The Silent Lovers, Emerald Point N.A.S., Crazy Like a Fox, Robocop (TV Series), Norma Jean & Marilyn, The Practice, Angel, The Guardian, 24, Amber Frey: Witness for the Prosecution, Barbershop, Day Break, Dirty Sexy Money, The Young and the Restless, Parenthood, Wizards of Waverly Place, Harry's Law, Desperate Housewives and The Mentalist.  He also has 27 composing credits and numerous stage credits.

John Rubinstein courtesy Melesse, via Wikipedia