The 49-year-old Oscar winner shares the screen with Lane in the upcoming thriller, years after revealing his crush on the actress. And as he told ET's Nischelle Turner at the film's press day in Los Angeles on Friday, he couldn't be more proud.
"I told her [about my crush], first thing, too. I said, 'Do you know long I've had a crush on you, Diane? Since [she starred in] Lonesome Dove,'" he boasted. "I told her straight up!"
Lane, 53, plays McConaughey's love interest in the new movie, and according to the actor, she exceeded all expectations. "[She's] fun and cool -- and she's a great actress. So, to be able to work with her was... it was a bit of a time travel, because when I had the crush on her, when it began with Lonesome Dove, I was really young and not even in this business," he marveled. "[Now] I've been doing it for 25 years. So, I time lept forward, and she doesn't look much different."
"I did the time travel and, I'm sitting here now with my crush in a scene that has some of that feel in it," he added.
Also starring in Serenity is Anne Hathaway, who remained a little more tight-lipped when it came to revealing which celeb she's crushing on. "I'm a happily married woman," she teased. "I didn't say [I don't have a crush], I'm saying I'm a happily married, respectful woman... so yes, there are people that make me flutter!"
'Serenity' Trailer: Anne Hathaway Hires Matthew McConaughey as a Hit Man
McConaughey noted that family life was a big topic of conversation between him and Hathaway on set -- who traded tips on how to keep that balance between work and personal lives. The pair formed an instant connection, however, while working on 2014's Interstellar.
"I knew I enjoyed working with Anne right away and would enjoy doing it again. When she came on board with this, it was like, 'Perfect!'" the father of three shared. "I really enjoy working with her."
"I felt very lucky when I met Matthew on Interstellar because he was... it's very unusual, you can admire actors from afar, and I had, and to meet someone up close and realize he's living his life, he's found the balance that I'm striving for," Hathaway expressed. "So, I just knew that I wanted Matthew in my life in some sort of influential way, and I hope that I'd be able to get to work with him, to continue to learn as an actor."
The pair has traded space exploration for a different kind of mystery based right here on Earth in Serenity -- and Hathaway doesn't want to give too much away. "I trust the intelligence of the audience," she insisted. "If you've seen the trailer, you have a sense of the vibe, the feeling of the movie."
"It's a sexual thriller, it's also a horror movie. I know for me it was," McConaughey said. "I'm like a detective in my own life trying to see if I'm real, if the world I'm in is real, is anything of this real? The only thing that my character knows is real is the love he has for his son. So, in that way, it's a love story, as well."
"[Watch the movie] with someone you think is sexy and smart, you'll have a great time," Hathaway promised.