It's reunion time on Supergirl! The first photos from the 100th episode are in and it reveals some fan-favorite characters are definitely returning for the landmark episode, namely Chris Wood's Mon-El. The actor teased that he could return when TV Guide spoke to him earlier this month.

"I was in Vancouver during the hundredth episode," Wood told TV Guide, when asked whether we should keep our eyes peeled for Mon-El. "And I went to the party. And that's as much as I can say." Well, now there are pics and we know that a return did happen.

TV Line has the exclusive first look of Mon-El back in his suit, and the site also confirmed that Odette Annable and Sam Witwer will return for the episode as Reign and Agent Liberty, respectively.

"The most exciting part — because we know we have a lot of people coming back — is just getting to work with cast members that I've not gotten a chance to interact with on set before," Nicole Maines told TV Guide on the red carpet for Supergirl's 100th episode party. "Also, just getting to see everybody together was just really fun!"

Discover your new favorite show: Watch This Now!

While the trip down memory lane will be fun for fans, it's going to force Kara (Melissa Benoist) to make a very difficult decision regarding her friendship with Lena (Katie McGrath). The episode synopsis reveals that Mxyzptlk (Thomas Lennon) returns to grant Kara a wish (his specialty) to go back in time and see how things would have turned out if she'd told Lena the truth about her identity before Lex could. Using this It's a Wonderful Life-inspired story, the episode will look back over key moments throughout the series, leaving Kara with a pretty huge decision: Does she want to change history to save her relationship with Lena?

It looks like the two former BFFs will at least have one brief moment of happiness together, but it won't last long if the episodic photos are to be believed. Kara embraces Lena in the photos, but Lena's face says she's not on the same page and hearts could be broken all over again. You can check all of them out — including some shots of the original D.E.O. crew — in the gallery below.

PICTURES: Look who is back for the Supergirl 100th episode

Katie McGrath and Melissa Benoist, Supergirl Photo: Katie Yu, Katie Yu/The CW

Supergirl's 100th episode airs Sunday, Feb. 23 at 9/8c on The CW.

Additional reporting by Megan Vick