'Lost' & 'Veronica Mars' alums set to sign on for 'Gossip' spin off

Cynthiawatros With Gossip Girl spin off leads Brittany Snow (young Lily) and Krysten Ritter (Lily's sister) cast, executive producers Josh Schwartz and Stephanie Savage have now set their sites on the ladies' supporting players.

As you may have already heard, Lipstick Jungle's Joe Bennett, Andrew McCarthy, will play the part of young Lily's pop. And now insiders confirm that Lost's Cynthia Watros will likely land the role of young Lily's mom.

Ryanhansen Also reportedly signing on is Veronica Mars' Ryan Hansen (Dick Casablancas) as a possible love interest for one of the sisters.

Excited by these prospects?  

The series -- focusing on Serena van der Wooden's mom, Lily, back in 1980s L.A. -- is set to debut May 11 as a Gossip Girl episode.