Drew Barrymore, who is looking trim after giving birth to her first child Olive just four months back, revealed her slimming secret while attending the New York City Ballet’s Annual Luncheon Benefit on Thursday.

The 37-year-old actress flashed a pair of Spanx’s control underwear under a skirt, when she was walking into the Manhattan theatre, the Daily Mail reported.

At first, her long, floaty skirt, with a black-and-white tie-dye pattern, appeared to keep everything covered but as she walked, its thigh-high slit became glaringly apparent, so did her black Spanx.

The curve tightening-underwear can be used to hide bumps and bulges, but it appeared that Barrymore wore hers as a kind of slip as she feared revealing too much.