In the first two Thor films, Natalie Portman played the role of Jane Foster, the astrophysicist and love interest of the God of Thunder. In Avengers: Age of Ultron Thor explained her absence by bragging about her work in the scientific community and also presented the subtle-not-subtle possibility (extreme likelihood) that the couple was facing problems.
According to Entertainment Weekly, Jane and Thor have broken up by the time Ragnarok begins.
The actor of the titular hero, Chris Hemsworth, said
He’s off exploring the universe, still trying to police it and control the mayhem. But he’s certainly enjoying being a drifter, being a solo cowboy out there.
Tessa Thompson (right) will be playing Valkyrie in the upcoming Thor film.
Marvel Studios president Kevin Feige said
We wanted Thor to encounter somebody that was near his equal and that his relationship with Jane may have evolved in unexpected ways in between The Dark World and Ragnarok and we wanted to pit him against a character who was much more his equal and in many ways his superior. Valkyrie is trying to not embrace any sort of Asgardian heritage that she has. Thor thinks maybe that will create a bond between them and, on the contrary, she wants to forget it all entirely.