The couple has signed on to star in director Kirk Harris' new movie "Dakota", about a service dog that helps a struggling war widow save the family farm.
Fox will play the widow and Green is set to portray an army official who helps bring her late husband's beloved dog home after he is killed in action.
Filming on the project will begin this summer.
"Having Megan and Brian star together is really cool for us as we certainly won't have to manufacture the kind of chemistry and magic that makes a family film like this so special!" producer Andrea Iervolino says.