What is Tom King Writing With Booster Gold and Harley Quinn?

For the second time in a week, Batman and Mister Miracle writer Tom King has tweeted out a message to his followers suggesting that he is working on a Booster Gold story -- but this time, he included Harley Quinn for good measure.

Last week, King tweeted that he was working on a secret new project.

"Working today on a new number 1 for a secret thing I'm not allowed to talk about," King posted. "Not even sure I'm allowed to say I'm working on it now. Hm. Just in case, do me a solid and don't read this tweet."

When a reader expressed hope that King was working on Booster Gold, the writer took a photo of his computer screen, revealing nothing about the story except the fact that Booster was indeed in the issue and speaking (well, screaming).

Today, King followed up a little more explicitly, posting a photograph of two action figures -- Booster Gold and Harley Quinn -- with the caption "Next."

Booster and Harley are two members of a very elite group among big-two superheroes: characters created after about 1980, who have remained relevant and popular.

Most major superheroes who have enough of a following to be featured in their own title were either created in the Golden and Silver Ages of comics, or are derivative of older characters (think new Green Lanterns and Batman characters, or somebody like the new Captain Marvel or Ms Marvel).

Both Marvel and DC have had a difficult time generating popular new intellectual property in recent years, which makes characters like Booster Gold (created in 1986 by Dan Jurgens, who wrote and drew the character's first series for two years) and Harley Quinn (created for Batman: The Animated Series) kind of special.

Harley has gone on to headline one of DC's best-selling comics. Booster has not had an ongoing series since 2011's Flashpoint reboot, but the series that ended for Flashpoint had fun for 49 issues -- a significant run in the current comics market for a hero who is not an A-lister.

Both characters have somewhat tortured backstories but are mostly associated with comics that have a humorous bent to them.

While Harley has been one of the most visible characters in DC's New 52 and Rebirth publishing initiatives, Booster's appearances have been infrequent and sporadic over the last six years or so. He is currently appearing -- and his post-Rebirth continuity being cleaned up -- in Action Comics, written and drawn by Jurgens again.

More on this as it develops, surely...!