Katy Perry posed in a jaw-dropping silver gown on Instagram.The pop star displayed her baby bump in the stunning look by Balenciaga.Perry is expecting her first child with fiancé Orlando Bloom.Katy Perry is pregnant with her first baby, and the "Daisies" singer has been pulling out all the stops when it comes to her maternity style.Posting three selfies on Instagram, Perry showed off a floor-length silver gown.