The star pair are in talks to appear alongside one another in a big screen adaptation of Olen Steinhauer's spy novel All the Old Knives.
Both Elba and Winslet have reportedly agreed that they will only accept their roles if the other agrees to work on the movie, according to the Daily Mail newspaper.
All the Old Knives will be directed by Neil Burger, who worked with Winslet on Divergent. Burger wants to cast the pair as former lovers and CIA operatives in the film, which would see the 41-year-old actress play Celia and the 'Luther' actor as Henry.
Although the pair are yet to confirm the deal, if they do sign up for their roles they will begin shooting later this year.
Elba is set for a busy 2016 and will be filming the second series of his Discovery Channel programme Idris Elba: No Limits later this year and is recording vocal parts for his animated character in Disney sequel Finding Dory.
Winslet has been nominated for the Best Supporting Actress BAFTA for her role in Danny Boyle's Steve Jobs as Joanna Hoffman, a role for which she was awarded the Best Supporting Actress in a Motion Picture Golden Globe last weekend.