Goldblum, 63, will play Grandmaster, a cosmic being who plays chess with lesser life-forms such as humans, said The Hollywood Reporter.
Urban, 43, will play Asgard warrior Skurge.
"The continuation of the epic Thor franchise will be powerful and unique, and with the additions of Cate, Jeff, Tessa, Karl and Mark to the cast, we have the makings of his most dangerous and heroic adventure yet," enthused producer Kevin Feige in making the announcement.