In the last season of "Supergirl", we got a chance to see "Supergirl" and "The Flash" work side by side for the first time. The two superheroes were up against Silver Banshee and Live Wire. Considering that both shows are now on one network, the two characters will now have a very special musical episode which will feature a popular Batman villain.

Executive Producer, Greg Brelanti revealed that the untitled musical episode will feature the Batman Villain, Music Meister, who has the power to sing at a high pitch that hypnotizes people and causes them to sing and dance. "We're very excited about it. There's great musical talent on both shows," CW president Mark Pedowitz said to TV Line.

There are still no official announcement on the actor who will play the Music Meister but fans are hopeful that the "A Series of Unfortunate Event" actor Neil Patrick Harris will take the role. Harris was the voice of the Music Meister in the "Batman: The Brave and the Bold" animated series. 

"We're certainly huge fans of [Harris], and as the casting process proceeds, we'll see what happens," Kreisberg said.

For those who doubt the singing abilities of "Supergirl" and "The Flash", a gig in the Fox TV series, "Glee" is a good sign. Grant Gustin played Sebastian Smythe, the leader of the acapella group, the Warblers and Mellissa Benoist played the shy and sweet girl Marley Rose.

"What's so crazy about a villain that can make you think your friends are singing and dancing in front of you?" Andrew Kreisberg said last year in a report by ComicBook about the upcoming musical crossover of "The Flash" and "Supergirl". The second half of "Supergirl" returns on the CW network on Monday, Jan. 23, 2017.