Pom Klementieff had just checked into her hotel room in London, and she was still relishing the butter chicken she had consumed an hour ago.

“It’s summertime, but it feels like winter — because London is always like that,” she said in a call last month. “So I’m like, ‘OK, I need Indian food.’”

The 37-year-old actress, known for her fan-favorite turn as the empathetic alien Mantis in Marvel’s “Guardians of the Galaxy” and “Avengers” films, was on the second city of the world promotional tour for her next superventure, “Mission: Impossible — Dead Reckoning Part One,” in which she plays an assassin hunting Tom Cruise’s character.

“I love playing a villain,” Klementieff, chipper and candid, said of her character, Paris, who was based on a male character from the original TV series that inspired the “Mission: Impossible” films. “There’s something cathartic and a little bit insane about it that’s really enjoyable.”

The seventh “Mission:…