Cruise, 51, plays military PR man Maj. William Cage, a quick-talking coward who is forced to fight for humanity against an alien invasion. Blunt is the poster girl for the Army, a highly trained warrior and the only person who can help Cage when he starts living the same day over and over again, never reaching the tomorrow of the title.
The director says three premieres in twenty-four hours is nothing compared to what they achieved on the set at Warner Bros.' Leavesden Studios in the U.K.
" 'Edge of Tomorrow' was an impossible movie to make — harder than anything I've ever done before. So having a premiere day that starts off sounding impossible really seemed like it would be a great way to finish," Liman said.
Cruise and Blunt joked about who will have more stamina on the day.
"Because I have a baby, I'm not sleeping as much anyway," Blunt noted.
"You'll be like, unconscious. But I'll be there," Cruise countered.
Cruise and Blunt were talking on the rooftop of a London hotel overlooking the opening location of the movie, where the main character is flown in to Trafalgar Square. It was the first time a helicopter has ever landed in between the famous fountains, next to Nelson's Column — something Cruise still gets excited talking about.
Despite shooting around the clock, the stars took time out when Blunt invited Cruise to a trendy London sex club to celebrate Matt Damon's birthday — a story she revealed on Jimmy Kimmel's U.S. chat show.
"He thought it was going to be a more civilized night," Blunt says. "But it was fun."
"Edge of Tomorrow" is in U.K. cinemas on Friday and opens in the U.S. on June 6.