<P> `` Duet '' is the seventeenth episode of the third season of The CW television series The Flash , which aired on March 21 , 2017 . The episode was written by Aaron Helbing and Todd Helbing from a story by Greg Berlanti and Andrew Kreisberg , and was directed by Dermott Daniel Downs . The episode features a musical crossover with Supergirl and reunites Grant Gustin and Melissa Benoist with their former Glee co-star Darren Criss , who portrays the Music Meister . Jesse L. Martin also reunites with Jeremy Jordan , with whom he previously worked in the 2012 musical film Joyful Noise . The story begins at the end of the Supergirl episode `` Star - Crossed '' , which aired on March 20 , 2017 , which saw Kara Danvers / Supergirl ( Benoist ) hypnotized into a coma by Music Meister , with Mon - El ( Chris Wood ) and J'onn J'onzz / Martian Manhunter ( David Harewood ) bringing her to Earth - 1 in hope that Team Flash can save her . </P>
<P> `` Duet '' is the seventeenth episode of the third season of The CW television series The Flash , which aired on March 21 , 2017 . The episode was written by Aaron Helbing and Todd Helbing from a story by Greg Berlanti and Andrew Kreisberg , and was directed by Dermott Daniel Downs . The episode features a musical crossover with Supergirl and reunites Grant Gustin and Melissa Benoist with their former Glee co-star Darren Criss , who portrays the Music Meister . Jesse L. Martin also reunites with Jeremy Jordan , with whom he previously worked in the 2012 musical film Joyful Noise . The story begins at the end of the Supergirl episode `` Star - Crossed '' , which aired on March 20 , 2017 , which saw Kara Danvers / Supergirl ( Benoist ) hypnotized into a coma by Music Meister , with Mon - El ( Chris Wood ) and J'onn J'onzz / Martian Manhunter ( David Harewood ) bringing her to Earth - 1 in hope that Team Flash can save her . </P>
what episode does supergirl go on the flash
what episode does supergirl go on the flash
Duet
Duet