Jared Leto has a bit of a reputation for being part of that stable of actors that will happily put their body through hell in the pursuit of performative excellence. No matter how much weight needs to be lost or how many used condoms need to be sent to cast members (allegedly), he'll go there if the part requires it. Hell, he'll go there even if it doesn't, seemingly.
His next role will see him taking on one of Spider-Man's strangest villains as Michael Morbius, a brilliant, tragic scientist turned pseudo-vampire with the usual penchant for drinking blood.
The role sees Morbius experiment with bats to cure a debilitating blood disease that has ravage his body leaving him a frail shell, painfully thin and weak. For that side of the role, Leto looks like he's channelled his weight-cutting days from before Dallas Buyer's Club, given how skeletal he looks in the trailer. And then when he gets all super-powered, he turns hench with rippling muscles and all of his motor skills unimpaired. It's a hell of a transformation.
But given the short filming schedule for the movie, you have to wonder how much of it was actually a real transformation. Given Leto's past experience, you'd think he'd shed a lot of weight for the "skinny Michael" sequences, but it seems the "real" Leto is actually the super-muscular one.
Having worked out incredible hard for his Joker performance - which involved eating every two hours - the Vegan rockstar actor bulked for Morbius, piling on more muscle as his Instagram from February 2019 (when filming kicked off) shows...
Presumably, the sequences showing him emaciated before he's empowered were created using a body double and effects work, but we will no doubt discover the ins and outs of it closer to the film's release. Particularly if Sony want to talk up the effects team, as you'd probably expect.