The Gwendoline Christie stormtrooper, who was chucked down a trash compactor at the end of Episode 7, made only a small appearance in The Last Jedi.
Warning: spoilers ahead.
Christie’s character appears for the first time very late in the film, when she meets and clashes with Finn (John Boyega).
The two battle, and it’s not long before she is given a spectacular, fiery death.
Johnson told IGN: “I mean, as you can see, man, we had a really full movie already.
“We had a big, big movie with a lot of characters we were trying to serve, and the God’s honest truth is, every character had to find their natural place.
“Phasma supports Finn’s storyline, obviously… and until she shows up to fight him at the end, look through the story that we have, there’s just not a lot of space to go into a big Phasma storyline in it.”
He added: “The truth is, it’s just a very big cast and you have to kind of pick your battles with it.”
The Last Jedi has been an enormous box office success, and also ranked very highly amongst critics.
It has split audiences, however, with Johnson having to fend off backlash over some plot elements.
Star Wars 8: The Last Jedi is out now.