CW's hit superhero series The Flash enters its third season this fall, and the incredible season 2 finale has fans buzzing about what we're going to see. Starring Grant Gustin as Barry Allen, the show is the second interconnected series in the Arrow-verse, which now includes Arrow, The Flash, Legends of Tomorrow, the animated series Vixen and Supergirl. News about the upcoming third season so far has focused on the introduction of the Flashpoint timeline, new faces coming to the show, and the inclusion of Supergirl (and Superman), with plenty of huge changes expected for this October.

Now, star Gustin gives fans something else to look out for in upcoming episodes with the reveal of a previously unnoticed easter egg that has been running since season 1 — and it's not something even die-hard comic book fans would recognize.

In an interview with TVInsider, Gustin revealed that since the beginning, a rubber duck has appeared in almost every scene at the Central City police station:

"No one seems to notice that we have a rubber duck that we’ve fit into almost every single scene in the police station. We have been doing it since early in season 1. Sometimes it’s in an evidence bag that a cop is carrying."

The Flash Earth-2 Justice League Easter Egg

The Flash is known for being packed full of easter eggs, with every episode including at least one reference to the Flash comics or the Justice League of America. Episodes set in Earth-2, in particular, are brimming over with details to delight the hearts of DC fans everywhere. However, it seems that no one has managed to notice the rubber duck snuck on set - which is surprising, given the obsessive way that fans of the show have pored over every episode looking for easter eggs just like this. Presumably, the ducky has remained unnoticed because it's not actually a comic book reference. Barry Allen (and the other members of the Flash family) don't have any real connection to a rubber duck, so there is little reason for even the keenest of fans to notice the addition.

It's fantastic to hear about silly in-jokes like this on set. Although the rubber duck may have nothing to do with the comics, knowing that Gustin and the rest of the cast are having fun while filming is enough to warm any fan's heart. Now that the secret's out, we are sure to see fans doing their best to spot the bath toy in upcoming episodes — we may even see it given a little extra attention if the viewers' response to the duck is a positive one.

Of course, this is nothing more than a silly way for the cast and crew to have fun on set, and fans may be disappointed to find that they can't actually see the duck in every police station scene. Gustin points out that it has been hidden in evidence bags (and presumably in other hard-to-spot places) in the past, so eagle-eyed viewers may be left unsatisfied. Still, this is one more thing to bring a little lightness to a show that has some truly dark moments, and if nothing else, it's a great excuse to re-watch seasons 1 and 2 before The Flash returns to screens in October.

Next: The Flash Casts Female Version of The Top

The Flash season 3 will premiere Tuesday October 4th at 8pm on The CW, Arrow season 5 will premiere in the same timeslot on Wednesday October 5th, Supergirl season 2 on Monday October 10th, and Legends of Tomorrow season 2 on Thursday October 13th.

Source: TV Insider