claim: David Attenborough did not serve as controller of BBC Two.
evidence: `` Worlds Finest '' is the eighteenth episode in the first season of the CBS television series Supergirl , which aired on March 28 , 2016 .. Supergirl. Supergirl ( TV series ). CBS. CBS. The episode 's teleplay was written by Andrew Kreisberg & Michael Grassi , and directed by Nick Gomez .. Nick Gomez. Nick Gomez. Andrew Kreisberg. Andrew Kreisberg. The episode features a crossover appearance by the title character of the CW series The Flash -LRB- also developed and produced by Greg Berlanti and Kreisberg -RRB- , marking the first episode of the series to feature a character from the Arrowverse , and the first character from a CW series to cross over to a CBS series before the show itself moved to the CW network .. Greg Berlanti. Greg Berlanti. CBS. CBS. title character. Flash ( Barry Allen ). The CW. The Flash. The Flash ( 2014 TV series ). Arrowverse. Arrowverse. The episode loosely intersects with the events of The Flash episode `` Versus Zoom '' .. The Flash. The Flash ( 2014 TV series ). Versus Zoom. List of The Flash ( 2014 TV series ) episodes#ep41. The episode reunites Melissa Benoist with her former Glee recurring co-star Grant Gustin , who portrays the Flash .. Grant Gustin. Grant Gustin. Melissa Benoist. Melissa Benoist. Glee. Glee ( TV series ). The episode title was inspired by the World 's Finest Comics series , in which Superman would team up with various other DC superheroes , including the Flash .. Superman. Superman