Classic crooner Tony Bennett joked about never singing for free, but made an exception for his pal Barbara Carroll on Saturday night at Jazz at Kitano. Bennett was in the audience at the Park Avenue hotel’s new supper club over the weekend to see his friend Carroll perform, and she invited him onstage at the end of her set to the delight of the surprised audience. With Carroll on piano, Bennett belted out Jerome Kern’s “I’m Old Fashioned” to a standing ovation. A spy reports he also told the crowd Carroll helped him at the beginning of his career, when he was going on auditions and “nobody wanted me.” Jazz at Kitano officially opens tonight with a gig by pianist Kyoko Oyobe.