Ever since Barry Allen (Grant Gustin) first appeared on Arrow alongside Oliver Queen (Stephen Amell), and subsequently spun off into his own solo series in The Flash, The CW has enjoyed bringing its superheroes together for crossover events. The first spanned individual episodes of The Flash and Arrow, the second worked to set up the network's third superhero series, Legends of Tomorrow, and the most recent was a three-night event that united heroes from all three series plus The CW's latest addition, Supergirl. However, the creators behind The CW's DCTV universe tried something a little different with The Flash and Supergirl musical crossover that aired this week.

This week's episode of Supergirl, 'Star-Crossed', introduced a new villain named Music Meister, played by Glee's Darren Criss, who "whammied" Kara Danvers (Melissa Benoist) before disappearing through a breach to Earth-1 in pursuit of the Fastest Man Alive. The crossover then properly took place in The Flash's 'Duet' as both Barry and Kara were stuck in an alternate reality where they broke out into song and dance. They were tasked with following the script of Music Meister's movie musical in order to escape - all in an effort to teach the superheroes about the importance of love.

Although the musical crossover event only took place in a single episode, it was a long time coming, having been confirmed last summer by Arrowverse producer Greg Berlanti during the Television Critics Association press tour - not to mention fans of The Flash, Supergirl and the rest of The CW's superhero series have been hoping to see a musical team-up for more than a year. Now that 'Duet' has finally aired, we discuss whether The Flash and Supergirl should do another musical crossover, or leave it as a one-and-done event.

Supergirl Flash Crossover Duet Music Meister Explained

In terms of whether or not Music Meister could return to facilitate another musical adventure, it's certainly possible. The lack of development concerning Music Meister's character may be one of episode's weaknesses, since the "villain's" powers are godlike, drawing comparisons to Supergirl's Mr. Mxyzptlk (Peter Gadiot). His plan appears to be stealing The Flash and the Girl of Steel's powers before doing an about-face and revealing he simply wanted to teach the superheroes a lesson about the value of love - a surprising, if anticlimactic, end to the conflict.

Still, because there seems to be no limit to Music Meister's powers, he's able to escape the S.T.A.R. Labs pipeline cell and disappear after explaining his reasons for whammying Kara and Barry. With Music Meister free and clear of any consequences for his trickery, The CW DCTV universe is able to bring him back anytime they wish. With little actually established about the extent of Music Meister's powers (for instance, it seems possible he can travel between Earths on his own, and simply utilized Kara's device to create a breach in order to lure her and her friends to Earth-1) the one thing we do know about Criss's character is that he likes meddling in people's lives. If Music Meister were to return, the writers would need to justify a reason for him to want to meddle in the lives of the characters.

Of course, with Music Meister's abilities and the possible list of reasons he could have for returning to teach another lesson seemingly endless, The Flash and Supergirl run the risk of abusing the character as a deus ex machina-like device for instigating and quickly resolving a musical storyline - which, arguably, they did in 'Duet'. Certainly, this week's musical crossover event is the first of its kind and, as such, benefits from its novelty and entertainment value, making viewers more forgiving in terms of contrived storytelling devices or poorly explained worldbuilding. (For instance, if Music Meister's alternate reality for Kara and Barry was a musical because they enjoyed musicals - not because of the nature of his powers - how and why did he get that name at all?)

Victor Garber Jesse L Martin The Flash Duet

That said, if 'Duet' proved anything it's that the talent involved The CW's DCTV universe, both in front of and behind the camera, is more than capable of pulling off a musical episode. For their part, Gustin, Benoist, Criss, and Jeremy Jordan (Supergirl's Winn Schott) all have experience in musical television series - the first three having appeared in Fox's musical dramedy Glee and the latter joining NBC's broadway-inspired series Smash for its second season. Both Glee and Smash featured more than one musical number per episode, meaning the cast members were required to learn the songs and dances, then perform them, along the same production schedule as a standard TV series. Undoubtedly, these experiences prepared the actors for their roles in 'Duet', which allowed The Flash to truly strive for something great.

Furthermore, even beyond Gustin, Benoist, Criss, and Jordan, the Arrowverse puts its best musical foot forward in 'Duet' by enlisting the likes of Jesse L. Martin (The Flash's Joe West), Victor Garber (Legends of Tomorrow's Professor Martin Stein), and John Barrowman (Arrow's Malcolm Merlyn) for additional singing roles. The actors are well known musical theater stars, and they helped elevate 'Duet' with their performance of Guys and Dolls' "More I Cannot Wish You". Carlos Valdes (The Flash's Cisco Ramon), too, has musical theater training, which becomes apparent in his number with Criss and Jordan, "Put A Little Love In Your Heart".

Unlike other famous TV musical episodes, 'Duet' doesn't force its non-musically gifted cast members to sing (like Alyson Hannigan, Nicholas Brendon, and Michelle Trachtenberg in Buffy the Vampire Slayer's "Once More, With Feeling"). This is largely because the Arrowverse has so many musically talented actors that even all those with musical theater experience weren't given singing roles in 'Duet' - most notably being The Flash's Tom Cavanagh. So, given the talent available to them in front of the camera, The CW had plenty to work with when it came to 'Duet.'

But even behind the camera, The CW enlisted some terrific talent. 'Duet' included two original songs, the first of which was "Super Friend" - a duet between Barry and Kara, which was written by creator/star of The CW's Crazy Ex-Girlfriend, Rachel Bloom. Meanwhile, 'Duet's closing number "Runnin' Home to You", sung solo by Barry, was penned by Oscar-winning duo Benj Pasek and Justin Paul (La La Land). The two numbers were undoubtedly the strongest in the episode since they were written specifically for the characters and the storyline, and offered two dynamic types of musical beats to 'Duet'. These songs, and the talent behind the episode as a whole, prove The CW has only begun to scratch the surface of the musical potential in its DCTV universe.

The Flash Supergirl Duet Barry Allen Kara Danvers

Still, even though the creative teams behind The Flash and Supergirl have proven they're perfectly capable of pulling off a musical crossover, the question remains whether they or The CW want to green light a repeat performance. In an interview with EW , Arrowverse producer Andrew Kreisberg said a musical crossover sequel ultimately depends on the fan reaction to 'Duet':

If we survive this one and the fans like it, as always with any of these things, we gauge the fan reaction to it. If it turns out to be a, “Yeah, that was cute, but don’t ever do that again,” we won’t. But who knows? Every time we do one of these things, like go to Earth 2 or have a musical episode, some of that stuff we gauge by the fan reaction. Like King Shark, people were so excited about that one minute with him, we were like, “Well, we’ve got to bring him back now!” So we’ll see what people say.

In terms of ratings, 'Duet' didn't improve too much upon The Flash's numbers from the week before, according to TV By The Numbers. The series remained steady in its rating with adults 18-49, while the number of viewers increased from 2.39 million to 2.65 million. However, The CW has never been a ratings heavy-hitter in comparison to broadcast giants ABC, NBC, and CBS. While The Flash doesn't necessarily show the same bump in the ratings The CW received for the 'Invasion!' crossover, 'Duet' has been well received among viewers, indicating fans would likely be open to another musical crossover event - perhaps even spanning a full two episodes.

Beyond ratings, though, 'Duet' was a successfully entertaining hour of television that managed to delight fans and allow its stars and creative team to fully shine through music and dance. The CW has stated over and over again that they're committed to yearly Arrowverse crossover events, adding an annual musical crossover to the mix gives the network a second event that can further endear the DCTV universe to fans and perhaps help garner higher ratings. With Music Meister on the loose, there's no reason story-wise for him not to return down the line. Plus, if the cast and creative teams of the Arrowverse are willing to make the musical crossover an annual event, fan response to 'Duet' indicates that would be a well received decision. So, should Supergirl and The Flash do another musical crossover? In short, yes.

Next: It’s Time For Supergirl To Fully Join The Arrowverse

Supergirl continues Monday, March 27 with ‘Distant Sun’ at 8pm on The CW. The Flash continues Tuesday, March 28 with ‘Abra Kadabra’ in the same time slot.