The "Harry Potter" star Watson is still in talks to play herself in the comedy movie which was formerly known as "The Apocalypse".
As for Segel and Krumholtz, the two have already closed the deal to make appearance in the film, The Hollywood Reporter said.
"End of the World" is inspired by a short called "Jay and Seth vs the Apocalypse", which stars Rogen and Jay Baruchel, who are held up in an apartment while dealing with the end of the world.
The upcoming film, meanwhile, will expand its story and involve not only Rogen and Baruchel but also James Franco, Jonah Hill, Danny McBride and Craig Robinson. The actors are all playing themselves as they get stuck in Franco's Los Angeles apartment during the apocalypse.
Segel co-produces and co-writes the script for "End of the World" along with his longtime collaborator Evan Goldberg.
The movie has been slated for a June 14, 2013 release in the United States. PTI JCH
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