Pike and Cruise teamed up for the new thriller and were put through their paces with a series of high-octane stunts, although the Brit was expecting her first child during the shoot.
And the former Bond girl admits she was stunned by how protective Cruise was over her - insisting she expected a star of his calibre to demand a replacement.
She tells Britain's Daily Mail, "He could not have been more supportive. Certain stars would have - or might have - said, 'Get someone else, she's pregnant!' That sort of thing goes on in this day and age.
"You don't know if you're going to have terrible morning sickness, whether you're going to suddenly balloon. I felt as if I had a secret stowaway.
"(He's a) big, iconic star who really is protective - and Tom was protective in a way I didn't expect. Sometimes you think after 30 years the performance might all be just for the camera - but you get all of it with Tom. Everybody gets all of it."
Pike is due to give birth next spring (13).