The creators of Smallville have been treating the fans to guest appearances from one comic hero or another fairly consistently since the fourth season of the show. It began with Aquaman's guest appearance, followed shortly by Cyborg and the Flash. Last season, Green Arrow and the Martian Manhunter became semi-regular cast members, and this season Lauren Vandervoot has joined the cast as Kara - the future Supergirl. According to KryptonSite, Episode 7.11 "Siren" will feature yet another figure from the comics. Oliver Queen (Green Arrow) will be accompanied by the Black Canary.
In the comics, Black Canary is one of the greatest martial artists in the DC Universe, and is endowed with the "Canary Cry" - a powerful sonic scream. She is a founding member of the Justice League of America (though she is not currently scheduled to appear in the Justice League of America film), and has had a long-term, off and on romantic relationship with Green Arrow, culminating in their marriage earlier this year.
At the present, what is known is that Chloe has been doing free-lance work for Oliver Queen, something bound to come up in that episode. "Siren" also comes the week after "Persona," the episode which will bring Braniac back to Smallville. However, it is currently unknown whether or not the romance between Black Canary and Green Arrow will be touched upon in this episode - and more importantly, how Lois will react to such a development.
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