"American Horror Story" alum Alessandra Toressani will make a cameo appearance in the 15th episode of "The Big Bang Theory" Season 9 as a children's sci-fi writer. Also, CBS finally released the official plot description for episode 15 'The Valentino Submergence' and what happened in last week's episode is recapped here for fans who missed it.

"American Horror Story" actress Alessandra Toressani officially signs in to guest star in the upcoming episode of "The Big Bang Theory" Season 9. According to Movie News Guide, the 28-year-old American actress will be playing the role of Claire, a children's science fiction series writer. Torresani's character will debut in the Valentines-themed episode of the CBS sitcom.

As for the official plot description of episode 15, Spoilers Guide notes, "Sheldon Cooper (Jim Parsons) and Amy Fowler (Mayim Bialik) host a live Valentine's Day episode of Fun with Flags, Leonard (Johnny Galecki) and Penny Hofstadter (Kaley Cuoco) grapple with getting older, Howard (Simon Helberg) and Bernadette Wolowitz (Melissa Rauch) find a surprise in their tub. Raj Koothrappali (Kunal Nayyar) is torn between Emily Sweeney (Laura Spencer) and Claire, the cute girl he met at the Bookstore."

For a quick recap of "The Big Bang Theory" Season 9 previous episode 14 entitled "The Meemaw Materialization", Christian Post reports that Sheldon introduced his dearest meemaw (guest star June Squibb) to his friends Leonard, Howard, Penny. Sheldon also introduced his grandmother to his girlfriend Amy however, the two had a not so good meeting. 

"The Big Bang Theory" Season 9 Episode 15 is entitled as "The Valentino Submergence". The forthcoming episode is slated to premiere on Thursday, February 11, 2016 at 8:00 p.m. exclusively on CBS.

"The Big Bang Theory" (abbreviated as TBBT) is an American situational comedy created by Chuck Lorre and Bill Prady. The storyline revolves around the lives of five characters residing in Pasadena, California.