The Flash season 3 episode 17 promo: The ‘Duet’ musical with Supergirl’s almost here

The Flash season 3, episode 17 is right around the corner, and based on what we know about “Duet,” this one’s going to be big. It’s the much-anticipated musical that will feature many of the characters from Supergirl, and then also someone in John Barrowman who’s better known for Arrow and Legends of Tomorrow. It’s the musical episode that’s been hotly-anticipated, and as a result of that, it only makes sense that the show promote this like nobody’s business. There will be songs, humor, and an appearance from former Glee star Darren Criss as the evil Music Meister.

Also, we know that the story here will begin in the closing minutes of the March 20 episode of Supergirl entitled “Star-Crossed,” so it may be important for you to watch that if you want to get the springboard for what we have here. (With that said, we don’t think it’s necessarily — the last thing we want to do is hype up that episode like many did the Supergirl episode leading to the “Invasion!” crossover from the fall.)

Synopsis – “Barry (Grant Gustin) and team are surprised when Mon-El (guest star Chris Wood) and Hank Henshaw (guest star David Harewood) arrive on their Earth carrying a comatose Supergirl (guest star Melissa Benoist) who was whammied by the Music Meister (guest star Darren Criss). Unable to wake her up, they turn to Team Flash to save her. However, the Music Meister surprises The Flash and puts him in a similar coma, one that Team Flash can’t cure. Kara and Barry wake up without their powers in an alternate reality where life is like a musical and the only way to escape is by following the script, complete with singing and dancing, to the end.”

The fact that some of this episode takes place within an alternate reality may be a bummer to some just because it’s not clear how much of the story will be relevant — for example, will the characters wake up with their memories of what happened there intact? There are a lot of questions, but we think this will easy be a ton of fun to watch. We know already that Rachel Bloom of Crazy Ex-Girlfriend wrote one of the songs.

The Flash season 3 episode 17 promo – Check out the longer clip below! Rather fantastic, no?

For more news on The Flash, including a review for tonight’s episode (posted after it airs), head over here! Also, be sure to share your early expectations in the comments. (Photo: The CW.)