John Wesley Shipp, who played the title character in CBS' 1990s series "The Flash," has boarded the project.

Barry Allen, meet Barry Allen.

The CW's The Flash has snagged Dawson's Creek star John Wesley Shipp, who played The Flash in the early 1990s CBS television series, The Hollywood Reporter has learned.

Shipp will guest star in the pilot playing a mysterious character. Details for his character are being kept close to the vest. If the proposed Arrow spinoff receives a series order, his role would expand to recurring status.

Grant Gustin stars as Barry Allen/The Flash in The CW pilot, which serves as an origin story similar in vein to Arrow. Barry -- introduced in Arrow's two-part winter finale in December -- is a Central City assistant police forensic investigator who visits Starling City to look into a series of unexplained robberies that may have a connection to a tragedy in his past. Through a freak accident, he is given the power of super speed that transforms him into the fastest man alive.

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The news comes as The Flash pilot nears the end of its casting process. Shipp joins a cast that includes Tom Cavanagh as physics "rock star" Harrison Wells; Jesse L. Martin as Detective West; Candice Patton as West's daughter and Barry's love interest Iris; Danielle Panabaker as Caitlin Snow, a bioengineering expert; and Rick Cosnett as Detective Eddie Thawne. This leaves one main role open: Hartley Rathaway.

Arrow's Greg Berlanti, Andrew Kreisberg and director David Nutter will serve as executive producers on Warner Bros. TV's eyed spinoff. Berlanti, Kreisberg and DC Entertainment's Geoff Johns will write the pilot script, with Nutter directing. Melissa Kellner Berman will serve as co-executive producer.

Flash originally was slated for a backdoor pilot on Arrow airing in the second half of the season, similar to how The Vampire Diaries helped launch spinoff The Originals last year. The change in tune is an effort for Flash to debut "with a bang like we launched Arrow," The CW president Mark Pedowitz told reporters in January at the TCA winter press tour.

CBS' The Flash aired 22 episodes during the 1990-91 season, getting the ax after struggling against tough competition from Fox and NBC's strong Thursday primetime lineups before being relegated to Saturdays.

Shipp, repped by Stewart Talent, starred as patriarch Mitch Leery in The WB's Dawson's Creek and most recently recurred on MTV's Teen Wolf as Isaac's father.

Email: Philiana.Ng@THR.com

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