'Stranger Things' writers say Winona Ryder and David Harbour improvised their kiss in the season 4 finale

• Warning: Spoilers ahead for the "Stranger Things" season four finale.
• The Netflix series' writing team revealed that a number of scenes in the finale were improvised.

"Strangers Things" stars Winona Ryder and David Harbour improvised their kiss during the season four finale, according to the show's writers.

After the release of the final two episodes of the latest season on Netflix last week, the official Twitter account for the show's writing team shared some behind-the-scenes information about the finale.

In one of the posts, the writers revealed that the kiss between Jim Hopper (Harbour) and Joyce Byers (Ryder) during a particularly tense moment was not in the original script.

In the scene, Hopper tries to reassure Joyce after explaining that he is going to use himself as bait to kill multiple monster Demogorgons.

Since Hopper was already thought to be dead at the beginning of the season, Joyce responded: "I am not having another funeral." The pair then have a short kiss.

The "Strangers Things" writing team tweeted: "This kiss wasn't scripted, Winona and David added it on the day of filming."

This was not the only moment improvised by the actors. In another post, they shared that Caleb McLaughlin improvised part of the scene in which his character Lucas calls out for his sister, Erica (Priah Ferguson), while he's being beaten up by Jason (Mason Dye).

Jason, a popular athlete, attacks Lucas and his friends after believing they had something to do with the death of his girlfriend, Chrissy (Grace Van Dien), who was killed by villain Vecna earlier in the season.

Another improvised moment came during Eddie Munson's (Joseph Quinn) death scene.

In the finale, the character is attacked by flying Demobats. As he's about to die, Eddie tells his friend Dustin (Gaten Matarazzo): "I think it's my year, Henderson. I think it's finally my year. I love you, man."

The writers revealed that this last bit of dialogue — "I love you, man" — was improvised by Quinn in the moment.

"Stranger Things" has already been renewed for a final season. The show's creators, the Duffer Brothers, told the "Happy Sad Confused" podcast said that the episodes in season five will not be as long as season four, except for the finale.

Last month, the Duffer Brothers explained to Variety that the 2 1⁄2 hour run time was needed for the season four finale because there wasn't "a good spot to break it."

"Stranger Things" is streaming now on Netflix.