Thursday on TV: It’s a big day in Pasadena — it’s the 200th episode of ‘The Big Bang Theory’

It's "Big Bang Theory" day in Pasadena, Calif. And the city has named a street — well, an alley — after the show.

It's all in celebration of the show's 200th episodes, which airs at 7 p.m. on CBS/Ch. 2. And because, of course, the characters live in Pasadena.

In the episode, the gang throws Sheldon (Jim Parsons) a birthday party and invites a big-name guest — former "Batman" Adam West.

The guest list also includes Christine Baranski (as Leonard's mother, Beverly); Sara Gilbert (as Leslie Winkle) and Wil Wheaton (as Wil Wheaton).

By the way, "BBT" would have reached the 200-episode mark more than a month ago but the first season — way back in 2007-2008 — was cut short (17 episodes) by the writers' strike.

Elsewhere on TV ...

• "The Big Bang Theory" (7 p.m., CBS/Ch. 2): Sheldon and the gang celebrate his birthday in the series' 200th episode.

• "Grey's Anatomy" (7 p.m., ABC/Ch. 4): April and Jackson's relationship is recalled through a series of flashbacks.

• "You, Me and the Apocalypse" (7 p.m., NBC/Ch. 5): Jamie learns the truth about his wife; a potential messiah unearths Celine and Jude's genuine emotions.

• "American Idol" (7 p.m., Fox/Ch. 13): The last two finalists are announced; the top 10 perform

• "DC's Legends of Tomorrow" (7 p.m., CW/Ch. 30): A malfunction sends the heroes to the year 2046, where they are faced with a surprising version of the future.

• "Project Runway: All-Stars" (7 and 9 p.m., Lifetime): The designers must create red carpet gowns for the Academy of Country Music Awards.

• Men's college basketball: Montana State at Weber State (7 p.m., Ch. 14); Arizona State at Utah (7 p.m., P12N); Portland at BYU (9 p.m., ESPNU

• "Life In Pieces" (7:30 p.m., CBS/Ch. 2): John buys a pony.

• "Mom" (8 p.m., CBS/Ch. 2): Christy, Jill and Wendy agree to help Bonnie smuggle an illegal substance across the Canadian border.

• "Scandal" (8 p.m., ABC/Ch. 4): Cyrus and Elizabeth each launch new plots; Olivia continues to question what Jake is up to at the NSA.

• "The Blacklist" (8 p.m., NBC/Ch. 5): Liz searches for more information about her mother.

• "The 100" (8 p.m., CW/Ch. 30): Clarke is torn between mercy and vengeance.

• "Portlandia" (8 p.m., IFC): Kath and Dave's accident leaves them temporarily disabled.

• "Two Broke Girls" (8:30 p.m., CBS/Ch. 2): Max tags along with Caroline as she travels to Hollywood to discuss turning her riches-to-rags life story into a movie.

• NBA (8:30 p.m., ROOT): San Antonio Spurs at Utah Jazz

• "Elementary" (9 p.m., CBS/Ch. 2): Holmes' investigation into the attempt on his father's life pushes their relationship to the breaking point; the identity of Sherlock's mother is revealed.

• "How to Get Away with Murder" (9 p.m., ABC/Ch. 4): Annalise tries to stay ahead of Philip's threats; Wes and Laurel are faced with confusion as they investigate the death of Wes' mother.

• "Shades of Blue" (9 p.m., NBC/Ch. 5): Harlee decides to assist with Stahl's investigation.

• "Workaholics" (11 p..m., Comedy Central): The guys cause trouble at a museum.

• "Baskets" (11 p.m., FX): Free bottled water can't soften the sting of rejection during a family evening together.

• "Vikings" (11 p.m., History): King Ecbert tasks his son with rescuing Queen Kwenthrith.

• "Colony" (11 p.m., USA): Will is close to discovering his wife's secret.

• "Idiotsitter" (11:30 p.m., Comedy Central): Gene decides to organize a prom for GED students and invites her cyber bully.