Although he is 73 years old, he has shown no desire to retire and was persuaded to reprise his other iconic role, Han Solo, in the new Star Wars film.
Spielberg made reference to doing a fifth Indiana Jones almost jokingly while talking about how Ford and Hanks have both made four films with him.
"Now, I'll probably do an Indy 5 with Harrison, [so] it'll be five for Harrison, four for Tom... I've got to make another one with Tom, that'll be five for Tom, five for Harrison. And I think I'm going to leapfrog that way for the rest of my career. With Daniel Day-Lewis in everything else," he said.
Producer Kathleen Kennedy confirmed earlier this year that there were plans for a new Indiana Jones but she said "we haven't started working on a script yet".