Article continues below advertisementRachel Bilson's summer is heating up! The O.C. star shared an 18-photo Instagram carousel full of memorable summertime moments, including one smoldering snap of herself in a halter top bikini from Solid & Striped.Article continues below advertisementRachel Bilson Poses for Jaw-Dropping Bikini-Clad PhotoSource: @rachelbilson/InstagramRachel Bilson stunned in her two-piece.The 43-year-old looked confident - and stunning - as she captured the bikini-clad selfie.