A familiar face to Gossip Girl fans will soon show up on ABC.

Caroline Lagerfelt, who popped up often on that CW drama as Serena's grandmother, will guest star on an upcoming episode of Castle Season 5.

The long-time actress will take on the role of Angelica Henley, the wealthy employee of a murder victim whose case Castle and Beckett investigate. Look for the installment to air in October.

Castle kicks off a new season, meanwhile, on Monday, September 24.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.