'Gossip Girl': Blair and Dan make their romance public - video
The promo shows Blair (Leighton Meester) and Dan (Penn Badgley) planning a 'coming out' party in which they will make their relationship public.
The footage is from the episode 'Salon of the Dead', which also features a face-off between Serena (Blake Lively) and Diana (Elizabeth Hurley) and sees Gossip Girl attempt to crush Lola (Ella Rae Peck).
Showrunner Josh Safran teased that the love triangle between Blair, Dan and Chuck (Ed Westwick) will come "to an end point" in the season five finale.
"We always try to make our finales really exciting and juicy and fun," he said. "But in this one, it's like a bomb gets detonated and levels everything."
He previously opened up the possibility of Blair and Chuck reconciling, saying that the former couple "are never over".
Gossip Girl airs in the US Mondays at 8/7c on The CW. UK viewers can catch it Mondays at 8pm on ITV2.