While Mark will be reprising his role as scientist Bruce Banner/The Incredible Hulk for the fourth time after appearing in Avengers, Avengers: Age of Ultron and Iron Man 3, this will be Cate and Jeff's first appearance in the Marvel Cinematic Universe.
Cate will be playing the role of Hela, a powerful and mysterious villain, while Jeff will be playing the "eccentric" Grandmaster.
Mark will reprise his role as Bruce Banner for the fourth time
Marvel fans have been quick to praise the casting decision, with one Twitter user writing: "this movie just keeps sounding better and better," while another joked: "Marvel, you didn't need to call Grandmaster "eccentric" after you said Jeff Goldblum was playing him."
Producer Kevin Feige has spoken about the casting news, saying: "The continuation of the epic Thor franchise will be powerful and unique, and with the additions of Cate, Jeff… and Mark to the cast we have the makings of his most dangerous and heroic adventure yet.
"The sheer, raw talent each of these actors brings to the screen can't be quantified. Having any one of them join the Marvel Cinematic Universe would be an honour, and having all of them is incredible."
Fans have praised the cast for Thor: Ragnarok
The film reportedly follows Thor (Chris Hemsworth) as he returns to his home world Asgard following the events of Avengers: Age of Ultron. Since Thor and Bruce Banner were the only two Avengers who did not make an appearance in Marvel's latest release, Caption America: Civil War, the third Thor film could reveal where their characters were in the meantime.
James Bond hopefuls Tom Hiddleston and Idris Elba will also be reprising their roles as Loki and Heimdall, although it has been reported that Natalie Portman, who plays Thor's main love interest Jane Foster, will not appear in the third instalment.