Arrowverse, the CW crossover event "Crisis on Infinite Earths" in 2019, is expected to be bigger and more action-packed with more stars than any previous event. That's why fans need to make sure they're prepared for the upcoming excitement, including guest appearances by characters from past WB / CW shows.

In addition to characters from "Arrow", "The Flash", "Supergirl", "Black Lightning" and "Batwoman" are in the crossover, which starts on Sunday evening, also cameo of older DC broadcasts to see z. Smallville "and" birds of prey ".

That's right, Tom Welling's Clark Kent and Ashley Scott's Huntress will turn up in the upcoming Arrowverse episodes.

Whether you've seen "Smallville" and "Birds of Prey" when they first aired, and you want to watch again or "come back" for "Crisis on Infinite Earths," read on to find out where They stream online for free and can be purchased there for offline viewing.

"Birds of prey" (2002-3)

"In the future, Batman has gone into exile, leaving the criminal city to a new group of female superheroes: Black Canary, Oracle, and The Huntress," CW Seed summary. "Working with an honest policeman, the Vigilante trio are using their meta-human powers to face the dark forces that are infesting the streets of New Gotham City."

Occupation: Ashley Scott, Dina Meyer, Rachel Skarsten, Shemar Moore, Mia Sara, and Ian Abercrombie

Where can you look online: The one-season short-lived series can be streamed for free on CW Seed and on DC Universe with a subscription (or a free seven-day trial). Episodes can also be purchased from Amazon Prime Video, YouTube, iTunes, Google Play, and Vudu for $ 1.99 each. The cost of purchasing the single season of the show in its entirety for the above services starts at $ 19.99.

Smallville Cast watch show online Binge all "Smallville" online before characters from the series appear in Arrowvers crossover "Crisis on Infinite Earths". Photo: The WB

"Smallville" (2001-11)

"This modern retelling of Superman mythology as an action series combines realism, adventure and emotion," according to the YouTube summary. "Years ago, a meteor shower rained destruction on an unsuspecting Smallville in Kansas. Out of this tragedy emerged Clark Kent (Tom Welling), who, as he learns to deal with his emerging superpowers, is approaching the legendary hero. "

Occupation: Tom Welling (Clark Kent), Allison Mack (Chloe Sullivan), Kristin Kreuk (Lana Lang), Michael Rosenbaum (Lex Luthor), John Glover (Lionel Luthor) and Erica Durance (Lois Lane)

Where can you look online: Subscribe to all 10 seasons of the drama in Hulu or buy episodes on iTunes, YouTube, Amazon Prime Video, Google Play or Vudu starting at $ 1.99 per episode. Whole seasons of the series cost at least $ 29.99 per season on the above platforms.

Arrowver's "Crisis on the Universe" begins with the "Supergirl" episode on Sunday at 8pm CW. EUROPEAN SUMMER TIME.