The official cast of Marvel Cinematic Universe's (MCU) upcoming instalment "Thor: Ragnarok" has been revealed and Natalie Portman won't be returning as Thor's love interest Jane Foster.

However, fans will get to know the reason behind her absence from the movie. According to Design & Trend, Marvel Studio's President Kevin Feige has said that though Portman won't appear in the third Thor movie, fans won't be disappointed as "there are many reasons behind it."

"Many of which are in the film so you will see that," Feige said.

Fiege further talked about the setting of the movie, saying, "There are only a couple of scenes on Earth in this [Thor] movie; 80 to 90 percent takes place in the cosmos."

Apart from Portman, Stellan Skarsgård, who played astrophysicist Erik Selvig in the first two movies, is also not mentioned in the cast list. Hence, there is a significant possibility that the God of Thunder won't stay on Earth for long in "Ragnarok."

Though Fiege has said that Portman is out due to particular reasons, Screen Rant has reported that according to several rumours, the actress decided to quit when the original director of "Thor: The Dark World" was fired by the studio.

The new cast includes Tessa Thompson ("Creed" and "Dear White People") and Cate Blanchet of "The Curious Case of Benjamin Button" and "Lord of the Rings" fame. They might play a love interest of Thor.

According to Christian Today, Blanchett might be playing the role of Hela, Loki's daughter, or The Enchantress, while Thompson is rumoured to play Brunnhilde - the Valkyrie. However, there has been no such official confirmation yet.

Chris Hemsworth, Tom Hiddleston and Mark Rufallo will reprise their roles of Thor, Loki and Bruce Banner'Hulk from previous MCU movies. Jaimie Alexander will also be back as Lady Sif.

"Thor Ragnarok" is scheduled to release worldwide on Nov. 3, 2017.