Bradley Cooper and Jennifer Garner‘s relationship is strictly platonic despite the duo’s fun-filled day at the beach earlier this week.“They are friends and have been forever,” a source tells Us Weekly of the pair, who costarred together on the TV series, Alias, in the early ’00s.Cooper, 45, and Garner, 48, sparked romance rumors when they were spotted together at a beach in Malibu on Wednesday, August 5.