According to E! Online, Brad Falchuk revealed that the couple, played by Cory Monteith and Lea Michele, will "stay together".
"That relationship is so much pushing and pulling and pursuing and going after each other," he said. "And now they're together. So this season, it's delving into two worlds that are really trying to meld together. It's the slusher [and the] slushee. What happens when those two, Romeo and Juliet, get together?"
Falchuk suggested that the show will examine how Rachel reacts to her new relationship with Finn.
"We're also exploring the Rachel character who wants things so much," he said. "And what happens when the girl who wants things so much gets the things she wants? I think that's going to be really hard for that kind of girl."
Meanwhile, Monteith admitted that he is "excited" about the storyline and Michele said: "I think it's going to be interesting to see what Rachel is like in a relationship as someone's girlfriend."
The show's creator Ryan Murphy added that he decided to put the couple together because the fans wanted it to happen.
"One of the things I love about [Finn and Rachel] is how different they are," he said. "And how does a couple, when they lose, how do they react? Do they fight about it? Do they love each other more? I know people love Lea and Cory together and so we are giving them what they want."
Glee returns for a new season on September 21 on Fox.