Warning: The following contains spoilers for CBS "Supergirl."

Who saw that one coming?

On the latest episode of CBS' "Supergirl," David Harewood's Hank Henshaw revealed his true identity. Turn back now if you don't want to know.

In the two clips below, Hank Henshaw unveils the truth for Chyler Leigh's Alexandra Danvers. To the delight of comic book fans everywhere, Hank turned out to be J'onn J'onzz, otherwise known as the Martian Manhunter.

J'onn J'onzz is one of the most popular members of the Justice League and, like Supergirl, one of the last of his kind. His exclusion from Warner Bros.' DC Extended Universe on the big screen has been a sore spot for many fans, making his introduction on "Supergirl" all the more enjoyable.

In the comics, J'onn J'onzz is the last surviving inhabitant of Mars. When stranded on Earth, he joins the Justice League as the Martian Manhunter. His abilities include shape shifting, flight, super strength, telepathy and more. Hopefully, he'll play a major role in the showing as his true self going forward.

What did you think of the big reveal, "Supergirl" fans? Let us know in the comments below.

The mid-season finale of "Supergirl" will air on Monday, December 14 at 8 p.m. et on CBS.