Watch: Laura Dern reveals why she came back for Jurassic World Dominion
Dern had not played Sattler since a brief appearance in 2001's Jurassic Park III, which she shot in a single day, but was enticed back for director Colin Trevorrow's epic trilogy-closer.
"The conversation started a couple of years before. 'Would I ever? What would it take? What would it look like? What did I think Ellie Sattler would be doing today?'" said Dern.
She added: "Steven Spielberg is fiercely protective of his babies, his characters.
"Colin really wanted to deeply honour that legacy of the first movie and capture the dynamics of those characters. But I think he also really cared, as Steven did, to give Ellie Sattler a return."
Dern said that Trevorrow and co-writer Emily Carmichael's choice of career path for Sattler made her even more inclined to step back into the famous role.
She said: "The emphasis and the focus was an environmental one and to consider that she would care deeply about climate change science and work in the area of soil science made me really want to be a part of it."
Dominion follows the new and old Jurassic characters as they reckon with the impact of a world in which humans and dinosaurs are being forced to live alongside each other.
Trevorrow and his team have always been keen to explain that the role of the legacy characters is a key one and that their appearances are far more than cameos.
Dern said: "We want all of these people to be the leads of the story, which is a lot to do in one film. It's kind of amazing what they figured out a way to achieve in storytelling."
The question now inevitably turns to the future. Dominion is being marketed as a conclusion to the franchise, but it seems very likely that there will be another Jurassic movie at some point — would Dern come back again?
"I didn't think about it the first time, so I haven't thought it about it this time," said the actor.
She added: "It feels like a culmination and there are so many stories to tell, including with some amazing new characters. I'm not sure, but I've learned to believe never say never.
"We did our show Big Little Lies, which was a one-time experience that ended up not being so. If you're lucky, you get to play characters again and again that you love."
Jurassic World Dominion arrives in IMAX and UK cinemas on 10 June.
Watch: Laura Dern and Sam Neill in Jurassic World Dominion