It was reported last year that Parker had written a treatment for a second film, after the success of the first which made over $130 million (£83m) worldwide.
"It seems almost comic to me that after wrapping it up so ruthlessly at the end of the first one that we'd be back there," Parker admitted to HeyUGuys.
"None of us thought so. But yes, the cast all really want to which is nice, and now it's not a surprise that Fox want to because obviously it did business."
Parker confirmed that he will write the script, and also implied that director John Madden is likely to return for the second film if it goes ahead.
Commenting on rumours that Helen Mirren and Colin Firth are set to join the cast, Parker said: "That was wildly premature, being that there was no script.
"But I do like writing for people and imagining that it's going to be someone, and the surreal thing about the film is that they are almost completely the people that I had in mind."
Watch the trailer for The Best Exotic Marigold Hotel below: