'Supergirl' Reveals How Long Mon-El Has Been Gone

Supergirl brought back a fan-favorite in tonight's episode, and answered a pretty big unanswered question along the way.

Spoilers for tonight's episode of Supergirl, 'Wake Up', below!

Tonight's episode saw the return of Mon-El (Chris Wood), who had previously been sent away in a pod during the Season 2 finale. Kara Danvers/Supergirl (Melissa Benoist) and company attempted to determine how Mon-El safely returned to Earth, and had been changed pretty drastically in the process.

As Mon-El quickly revealed, his journey back to Kara was way more complicated than it appeared on the surface. His pod was sent into the future - where he spent seven years amongst the citizens of the 31st century.

While it's unknown exactly what Mon-El was up to in that period of time, we do know two things - he was cured of his lead poisoning, and he married Imra Ardeen/Saturn Girl (Amy Jackson) in the process.

In a way, fans should have seen this coming, considering the notion that Mon-El's return would be rather unexpected.

"In Episode 7, it's pretty mysterious. I think this season, we've really delved into a different tone, a different atmosphere for Kara," Benoist said earlier this month. "She's really figuring out how to own her alien-ness, if you will, and in turn I think she's finding her womanhood at the same time through grief and that grief is apparent even in the coloring of the show, so I think it's a long-- it won't be the reunion you expect."

So how will that factor into the future episodes of Supergirl? Fans will just have to wait and see.

Supergirl airs Monday nights at 8/7c on The CW.