A user on Twitter posted that he recently seen Zachary Levi and that he "definitely has the strength of Hercules, is absolutely freaking JACKED [right now], and is gonna totally kill it."
Back in October saw a trainer remark about Zachary Levi's workouts, so we know Levi as been training since then.
I haven't been able to find a new image of Zachary Levi all jacked up, but here is Levi from October, and below is an image director David F. Sandberg posted on Jan. 3rd.
Shazam! gets released April 5, 2019 also starring Asher Angel as Billy Batson, Jack Dylan Grazer as Freddy Freeman, Ian Chen as Eugene, Jovan Armand as Pedro, with Cooper Andrews, and Mark Strong is rumored as the villain.