Marvel has become synonymous with secrecy. Any leak from an MCU set could potentially ruin an enormous surprise for fans, so the studio has taken every possible measure to avoid that throughout its near-20-year history.

Ruffalo has been part of the superhero franchise for 14 years, starring in all the Avengers movies and fan-favorite titles like Thor: Ragnarok. Last time we saw his Bruce Banner was in Disney Plus' TV series She-Hulk: Attorney at Law, which starred his cousin Jennifer Walters (Tatiana Maslany).