Brad Pitt proved he had soul when he joined Bruno Mars on-stage during his star-studded benefit gala May 17 for his Make It Right housing organization. The "Treasure" singer performed a funky cover of the James Brown hit "Sex Machine" while Angelina Jolie's significant other played the tambourine and danced along. Mars playfully sang, "Benjamin Button!", referencing Pitt's memorable man-child role in 2008's The Curious Case of Benjamin Button. He even called Pitt "a sexy motherfucker". Watch the two jam out above.