Greg Berlanti, executive producer of the DC shows, Arrow, The Flash, Supergirl and Legends of Tomorrow, recently announced a two-part musical crossover of The Flash and Supergirl at CW’s Television Critics Association summer press tour. According to That Hashtag Show, a source has revealed Joss Whedon is set both episodes.

Both The Flash’s Grant Gustin and Supergirl’s Melissa Benoist appeared on Glee, an episode of which Joss Whedon also directed.

Further rumours suggest that the big bad for the episodes will be the Music Meiester, a character created for the musical episode of Batman: The Brave and the Bold. Neil Patrick Harris voiced the character for the animated series and it wouldn’t be too far of a stretch to suggest that he may appear as the live action version of the character given his connection to Joss Whedon.

Watch the episode of That Hashtag Show where they discuss the possibilities and rumours below.

Source: That Hashtag Show