Britney Spears appears to be embracing her impending role as an aunt - after she was spotted buying gifts for her pregnant sister JAMIE-LYNN. The troubled pop star spent Thursday (20Dec07) afternoon buying baby clothes in Los Angeles. The singer, who discovered her 16-year-old sibling's news after she went public with the announcement on the cover of an American magazine, is reportedly vowing to support Jamie-Lynn's decision to keep the baby. The 26-year-old is currently locked in a bitter custody battle over her sons Sean Preston, 2 and Jayden James, 1, after recently losing primary custody to ex-husband Kevin Federline.