Jay Garrick, played by John Wesley Shipp on The Flash, may have had his connection to Earth-Prime severed following the events of The CW's "Crisis on Infinite Earths" crossover, but the hero is set to return in an upcoming episode of Stargirl. That means that Garrick, as in the comics, will now exist on Earth-2 -- an Earth-2 much more similar to its original comics roots than the one originally seen on The Flash. At the end of the Crisis, the heroes of Earth-Prime were led to believe that the rest of the multiverse had been eradicated, but audiences were clued in: it was still there, just out of reach.
Entertainment Weekly reports that Garrick plays a role "in a pivotal flashback episode" that establishes his membership in Earth-2's Justice Society of America, a team previously seen on the series. Garrick's helmet has popped up on the show already, but producers had stopped short of answering whether it would be Shipp, or a different actor, who eventually played the part if he appeared.
A statement from the network, also via EW, says Garrick's presence will "officially bring Stargirl into CW's post-Crisis CWverse alongside The Flash, Superman & Lois, Batwoman, Black Lightning, Supergirl, and DC's Legends of Tomorrow."
Black Lightning and Supergirl will end after their current seasons are completed, and Superman & Lois will debut next week, making 2021 a year of some serious flux for the Arrowverse (that's the unofficial moniker fans prefer to "CWverse") shows. The extent to which this crossover means Stargirl will be able to interact with future Arrowverse events is unclear at this point; there will be no crossover event this year as a result of the delays and production challenges presented by the COVID-19 pandemic.
Shipp previously confirmed that he will return to the Arrowverse an an appearance in the seventh season of The Flash, seemingly once again breaking down the walls between universes in the multiverse. The actor first played Barry Allen, the primary Flash now played by Grant Gustin, in a short-lived CBS series in 1990, and returned to play first Barry's father, and then the Earth-3 Flash Garrick, on the hit CW series.
Earth-2, which was ruled by Zoom and filled with dark versions of The CW's heroes, was the first universe destroyed by the Anti-Monitor's antimatter wave in "Crisis on Infinite Earths." When, at the end of the event, the multiverse was re-established, Earth-2 was no longer dark, but brighter than ever, featuring the heroes of Stargirl in its establishing shot.