Fans claim to have seen Supergirl's figure in Kelex's head in the Superman trailer. Potential narrative and familial ties between Superman and Supergirl suggest Alcock's cameo in Superman is possible.

Video: Supergirl star Melissa Benoist beams on set in her new costume as cameras roll on The CW series in Vancouver Tons of explosions and action in the trailer for Season 4 of The CW's 'Supergirl.' ...