In recent spoilers that have surfaced online, it is being suggested that the Joker will be making an appearance in season 2, episode 19 of Arrow.

Oliver Kills Slade in Episode 18?

Tim Beyer of the Motely Fool said that several references to the Batman franchise with the Dark Knight and other hints led him to believe that the Joker might grace viewers with his presence on the show:

"The next potential tie-in could come in episode 19 titled The Man Under the Hood. The story could refer to the original Red Hood from DC Comics lore, who goes on to become Batman's arch-nemesis, The Joker," Beyer stated.

Harley Quinn to Return? Actress Portraying Quinn Revealed

In the next episode, Death Stroke, Slade will hold good on his deadly threats to Oliver as he kidnaps his half-sister Thea. In the preview of the episode, Oliver is finally confronted with his arch enemy and is seen taking him down with his arrow.

Here's the official synopsis for the episode:

Thea Kidnapped By Slade, Learns Big Secret About Oliver that Creats A Rift in Episode 18?

"In the Deathstroke episode of Arrow, Slade (Manu Bennett) makes his move against Oliver (Stephen Amell) and the repercussions are enormous. While Oliver scrambles to protect his family, a key player in his team starts to question Oliver's decisions. Meanwhile, Isabel (guest star Summer Glau) makes her move to take Queen Consolidated away from Oliver."

Detective Lance Finds Out About Oliver's Secret in Episode 19?

Deathstroke will air on April 2 at 8 p.m. ET/PT on CW.

Watch the preview here: