Darren Criss and Chris Colfer Perform 'Glee' Reunion Duet in London

• Darren Criss performed at London's Royal Albert Hall on October 18.
• Chris Colfer joined Darren Criss on stage for a surprise duet.
• They performed 'It's Been Awhile' and 'Baby It's Cold Outside'.
• The performance was a tribute to their characters, Kurt Hummel and Blaine Anderson from 'Glee'.
• This marked their first joint performance in over a decade.