David Ramsey says lines as different characters from CW's Arrow.
He impersonates:
Colton Haynes as Roy Harper Red Arrow
Stephen Amell as Oliver Queen Green Arrow
Emily Bett Rickards as Felicity Smoak
Katie Cassidy as Laurel Lance Black Canary
Paul Blackthorn as Quentin Lance
and David Ramsey as Diggle

His full hour here    • Arrow's David Ramsey Diggle up close ...  

Watch his Barrowman impression in this video from earlier in the panel.    • Arrow Diggle David Ramsey Impersonate...