Britney Spears flashed a nipple during her Las Vegas residency on Wednesday night As she sashayed across the stage at the AXIS the Toxic songstress ended up flashing her nipple to her cheering fans. One such fan was actress and comedian Amy Poehler who went wild, showing her support for the pop star from the front row. Nov 02, · Britney Spears turns A look back at her chaotic life The "Toxic" singer suffered a similar nip slip in February when she popped out of a green one-piece on stage. Spears' residency opened at The AXIS . Britney Spears suffered a nip slip during her November 1 Las Vegas concert. See the racy pic here.