"The Flash" season 4 created a buzz before the show went on a winter hiatus. The talked-about "Arrowverse" crossover spectacle "Crisis on Earth-X" further stirred the speculations regarding the future of the newly-weds, Barry (Grant Gustin) and Iris (Candice Patton). Particularly, there was this scene prior to the wedding ceremony that caught the fans' attention, which showed Barry having a brief conversation with a waitress. Based on the rumors, this mystery waitress holds an interesting secret involving Barry and Iris, and this could be revealed in the series' mid-season comeback.

To recall the events in "Crisis on Earth-X," a waitress whole-heartedly congratulated Barry for his wedding. She even claimed that Barry and Iris' exchange of vows would become a moment to remember, although she reminded Barry not to forget to say "I do." As this was the first time the character was seen in "The Flash," it seems odd that a stranger would have a meaningful talk with Barry for his wedding, as if the wedding means a lot for her. This is where the rumors set in, suggesting that the mystery waitress is no other than Barry and Iris' daughter from the future, Dawn Allen.

According to the latest rumors, the revelation of the mystery waitress' identity might happen in the upcoming mid-season premiere of "The Flash." Episode 10, titled "Trial of the Flash," will reveal the repercussions of the previous events. Prior to the winter break, the fans were shocked as Barry was pointed as the suspect for the death of Clifford Devoe (Neil Sandilands). Interestingly, the upcoming episode has the same title of a popular comic book storyline, in which Dawn Allen enters the picture. 

The actress who played the mystery waitress in "Crisis on Earth-X" crossover, Jessica Parker Kennedy," revealed that her character will be seen again in the future episode. She did not confirm if she is actually playing the daughter of Barry and Iris, although she confirmed that her reappearance in "The Flash" season 4 will answer every question that the fans have at this point.

"I'll be around," Kennedy said in an interview earlier this month. "You'll see me at least one more time, I can tell you that... You'll see me again on the show and things will make more sense."

According to Comic Book, Barry was forced to time-travel to the 30th century due to certain events in "Trial of the Flash." That is when Barry will have her twin children with Iris, who are named Dawn and Don. It is not confirmed whether CW will follow the details of the original "Trial" plot, but with rumors saying that Barry's daughter already appeared in the show, there is an increasing likelihood that the series will follow this path.

"The Flash" season 4 episode 10 will air on Jan. 16 at 8 p.m. EST on The CW.