Stephen Amell is a huge wrestling fan and actually wrestled for WWE at 2015's SummerSlam. That led to a friendship with Cody Rhodes that's seen him also appear at independent and All Elite Wrestling shows, something which resulted in many fans believing that we'd seen the last of him in WWE.
Over the weekend, it was revealed that the Arrow star would be on last night's episode of WWE Backstage for "Promo School" but shortly before it went on the air, FOX's WWE Twitter account revealed that he'd been forced to drop out due to being "under the weather."
That's not an overly convincing explanation and speculation is running rampant that either WWE didn't want him there due to his All Elite Wrestling connections or that he may be under contract with that company. It could be he was legitimately unwell, of course, and if that's the case, we wish him a speedy recovery and hope to see him on WWE Backstage soon!