The Flash season 9, episode 7 trailer reveals the first look at the final Supergirl crossover, which includes Dreamer joining the show. The end is near for the Arrowverse's longest-running series as The Flash season 9 only has seven episodes left. After finishing the Red Death saga, the show is currently in its interlude phase with standalone episodes. Those will be leading up to the final storyline for The Flash season 9. Before the show ends, several Arrowverse characters will be showing up in Central City one last time.

Following the airing of "The Good, The Bad, and the Lucky," The CW (via TV Promos) released The Flash season 9, episode 7 trailer. Titled "Wildest Dreams," the trailer gives a first look at Supergirl's Dreamer joining The Flash, with Nicole Maines reprising the role.

Kristen Kim and Jeff Hersh wrote the episode, which was directed by Jesse Warn, and airs on Wednesday, March 29. The Flash season 9, episode 7 trailer features Nia and Iris West-Allen trapped inside a dream.

RELATED: The Flash's Season 9 Villain Origin May Explain How Oliver Queen Returns

What Other Arrowverse Characters Are Returning In The Flash Season 9

The Flash Season 9 Arrowverse Earth Prime

For The Flash season 9, there is another major episode coming up that will be a huge Arrowverse reunion. Episode 9, directed by Danielle Panabaker, will be a crucial one for not just The Flash, but the whole Arrowverse. Keiynan Lonsdale is reprising the role of Wally West, aka Kid Flash, for the final time in the franchise. Sendhil Ramamurthy is also back as the villain Bloodwork.

The Flash installment will also include Arrow's Stephen Amell and David Ramsey as Green Arrow and Diggle, respectively. For Amell, it will be the first time he appears since Arrow season 8 in 2020. It's unclear how Oliver Queen is returning following his death in Crisis on Infinite Earths. Diggle was last seen in The Flash season 8 when they wrapped up the mysterious alien box storyline.

Whether or not other Arrowverse heroes will swing by one last time remains to be seen. With The Flash season 9 coming to an end, it's the essentially the conclusion of the Arrowverse. The Flash is the last Earth-Prime-based series in the franchise, with Superman & Lois set on another Earth. As bittersweet as it is, there is still a lot to look forward to in The Flash season 9 before it ends.

MORE: The Flash Season 9 Just Made 1 Arrow Villain More Dangerous Than Ever

The Flash season 9, episode 7 airs Wednesday, March 29 on The CW.

Source: The CW (via TV Promos)