Director Sefton Hill is teasing a new trailer for Batman: Arkham Knight that will feature a character returning from Batman: Arkham City.

Hill took to Twitter, saying that his initial plan to announce a trailer release date had been postponed because Rocksteady and WB Games had come up with a “much more exciting way to do this.”

So I promised a trailer date this week but then we thought of a much more exciting way to do this so you'll need to wait just a bit longer. — Sefton Hill (@Seftonhill) April 18, 2015

Not to rub it in but I reviewed the latest edit and it's looking sweet. You might well see someone familiar from Arkham City in there. — Sefton Hill (@Seftonhill) April 18, 2015

The trailer also shows off a very cool new feature to @BatmanArkham that no one outside of Rocksteady / Warner has seen before! — Sefton Hill (@Seftonhill) April 19, 2015

The list of characters Hill could be teasing is lengthy. Catwoman was playable in Arkham City, and Robin also made an appearance. Nightwing was playable outside of story mode. Hugo Strange, Talia al Ghul, Mr. Freeze, Calendar Man, Solomon Grundy, Ra’s al Ghul, Mad Hatter, Deadshot, and Hush all also appeared in Arkham City, but have not yet been revealed in Arkham Knight. And, of course, the Joker, who died at the end of Arkham City.

Batman: Arkham City is due for release June 23.