'The Flash's John Wesley Shipp Explains How "Flashtime" Works

When John Wesley Shipp brings Jay Garrick back to the world of The Flash on this week's episode, titled "Enter Flashtime," he will be fighting side by side with Grant Gustin's Barry Allen for the first time in a while -- and the two will get to spend some quality time together onscreen for the first time since Shipp played Henry Allen, Barry's dad.

But what will they be doing? Trying to defuse an active, exploding nuclear bomb, of course. And they will do it by way of Flashtime, the time-freezing trick previously seen in "The Trial of The Flash" earlier this season. In that episode, in the moment before Iris outed Barry's secret identity to the world in order to stop him from being convicted of a murder he did not commit, he froze time around her, and had a whole conversation with her between ticks of the clock, before taking his seat and "slowing back down" to meet up with time.

"I was talking to Sterling Gates -- and I have to tip my hat to Sterling and Todd Helbing, because the whole concept of this episode, I find so exciting. The idea that we all enter Flashtime, which almost but not quite freezes real time, and that if we ever stop, it's game over," Shipp explained. "And speedsters can't run forever. And so how long can we keep going? And can we keep going long enough to figure out a solution before we have to go back to real time, and it's game over? So I just think that concept is brilliant. And so, you've got us operating in Flashtime together."

The idea of Flashtime is different from entering the Speed Force, in part because Flashtime is still happening on Earth-1, in the current day, and the impact of what they are doing has direct, physical impact on the world around them in a way that a spiritual limbo-realm like the Speed Force does not.

"The stakes are higher because we're under an extreme time crunch," Shipp added. "So everything is heightened. It is the same idea going into the Speed Force, but this there's a heightened sense of what's gotta happen in a split second."

The Flash airs on Tuesday nights at 8 p.m. ET/PT on The CW. "Enter Flashtime" will debut tomorrow night at 8.