Just when you thought you knew everything you needed to leading into Avengers: Age of Ultron, a new mystery arises. Disney is getting ready to premiere the film later this month and in a list of cast members attending the red carpet premiere, two names jumped out: Julie Delpy and Linda Cardellini. Neither actress has been in a Marvel movie before but both are well-known, which suggests more than just a fleeting cameo. So what does this mean? Read more below.