Barbra Streisand proved she means business by collecting a check for a cool $2.3 million for singing at a banking conference at Lincoln Center on Friday, Confidenti@l has learned. The "Memory" singer was listed as the "surprise entertainment" at 2:45 p.m. on the schedule of investment firm Baron Funds' 22nd Annual Baron Investment Conference at the Metropolitan Opera House.

She arrived under a cloak of secrecy in a black SUV with tinted windows that parked at the loading dock. And Babs got paid the whopping figure for what amounted to a miniconcert, one attendee says. She belted out 10 tunes, including "Memory," "You Don't Bring Me Flowers" and "People," in just under an hour for the buttoned-up crowd. After her performance, she left just as stealthily as she arrived.