Rihanna, Helen Mirren have the Sexiest Stomachs :

R&B singer Rihanna has topped a new poll of the 'Sexiest Celebrity Stomachs in the World'. The 20-year-old Barbados-born beauty, renowned for her revealing stage outfits, came first in the poll conducted by stomach-flattening supplement AntiBloat, reports China Daily.

Second on the list was Keira Knightley, who is famous for wearing midriff-flashing costumes, and who has bared her taut abs in movies including ''Bend It Like Beckham'' and ''King Arthur''.