The 'Supernatural' actor was trending on Twitter after fans spotted him during the telecast on Sunday.
The angel gave his own life to save Dean in one of the series' final episodes.
Jensen Ackles, Jared Padalecki, Misha Collins were among those who posted tributes to the outgoing CW drama on Thursday.
Misha Collins and Alex Calvert also join in on the farewell message celebrating the show's final premiere night.
Watch a never-before-seen clip featuring series star Misha Collins.
The complete season 14 set is available on DVD and Blu-ray on Tuesday, Sept. 10.
ET exclusively debuts a first look at a featurette with Jared Padalecki, Jensen Ackles and Misha Collins looking back on season 14.
