Interstellar star Matthew McConaughey said he wouldn't want to go into outer space without his wife Camila and their three kids Credit: Steve Granitz/WireImage

Matthew McConaughey wouldn't give up his family for anything -- even the universe. The Oscar winner, 44, told reporters at the Hollywood premiere of his new sci-fi drama Interstellar on Sunday, Oct. 26, that he'd have to think twice about going into space for real if it meant leaving behind his wife, Camila Alves, and their three kids, Levi, 6, Vida, 4, and Livingston, 22 months.

"Oh, that's not easy to answer," the dad of three said when asked if, given the option, he'd venture into the great unknown. "I've got family and I don't want to be the guinea pig, and I'd have to see how long I'd be gone and if I could take them with me."

He went on to say that the evolution of his personal life -- he married Alves in June 2012, six months before the birth of their third child -- had a lot to do with the progression of his career. "I don't know how to directly say it, but I would say where I am today has a lot to do with my real life as well," he said on the red carpet outside TCL Chinese Theatre.

Indeed, McConaughey's offscreen roles as a husband and a father seem to have carried over to his relationships on set. According to his costar Mackenzie Foy, he and the rest of the cast were "like a little family" during filming.

"He was an amazing person, and he was a happy person," Foy, 13, told Us Weekly at the premiere. "He was just really nice."

She had similar words of praise for the star's kids, who were absent Sunday night but accompanied McConaughey and Alves to the American Cinematheque Awards last week. "They are adorable, and they're so sweet and polite," the Twilight Saga: Breaking Dawn actress gushed. "I adore them!"