AceShowbiz -

The story of Lily van der Woodsen and Rufus Humphrey's love child in "Gossip Girl" is not yet ended. An actor has been cast to be the half brother of Dan and Serena, and the character will be debuted for the first time in the season finale, airing May 18.

Chris Riggi, who had cameo roles in "Lipstick Jungle" and "The Guiding Light", has been hired to play Scott, the long-lost secret child of Lily and Rufus. E! Online who had the exclusive story, said that the return of Scott would be "a major grenade" in the Lily-Rufus relationship.

The existence of the lovechild was first introduced in the January episode called "Gone with the Will". Rufus sought the truth about a child he never knew and discovered that Lily ran away from their relationship in the past because she gave birth to a son overseas. The baby was adopted by a suburban family and the adoptive parents said that he died out of sailing accident but the truth came out that he was indeed alive and is coming to Upper East Side.

The finale will air on The CW Monday, May 18. Meanwhile, the May 11 episode has got a new sneak peek where a prom party is held and the queen and king are nominated.