Cyrus spoke with ET's Lauren Zima on the star-studded pink carpet outside The Theater at the Ace Hotel on Monday evening, and opened up about how her handsome hubby is resting up and trying to get better.
"Liam's feeling good. He has to, you know, rest up, but he loves this film," Cyrus shared. "He's so proud of it and I really wanted to be able to represent it for him."
While Cyrus didn't go into detail about why Hemsworth was recently hospitalized, she explained that "he just needs to take care of himself and getting healthy is more important than anything."
"[Also] I had my dress already and I couldn't let it go to waste," the 26-year-old singer said of her stunning Valentino gown, which was the perfect shade of Valentine's Day red for the romantic comedy's premiere.
Meanwhile, Hemsworth took to Instagram to apologize to fans for not being able to make it to the premiere, but thanked his wife for showing up in his place.
"Sorry I couldn’t make it to the @isntitromantic premier tonight guys. Been dealing with some pretty annoying health stuff the last couple days. Lucky I have the best girl in the world to represent for me! Thanks for the support babe!" the 29-year-old star captioned a slideshow of photos of Cyrus at the event. "I hope everyone enjoys the movie! It’s a perfect Valentine’s Day flick so if ya ain’t got nothin better to do then go see it! Love to all!"
Hemsworth's co-star, Rebel Wilson, also praised Cyrus for attending on his behalf, posting, "Thanks @mileycyrus for being Liam's stand in tonight, you're too cool x."
Speaking of Valentine's Day, this will be the first time the stars will celebrate the holiday as a married couple, after tying the knot back in December, and Cyrus said they don't exactly have any big plans.
"We'll end up probably eating something like Chinese food [and] lay in bed all day," she joked.
The star-studded premiere comes one night after Cyrus slayed on stage at the 61st Annual GRAMMY Awards, where she performed twice -- first with Shawn Mendes and again as part of the tribute to Dolly Parton where she and the country icon sang a duet of "Jolene" that was simply amazing.
Check out the video below for a look at some of the amazing performances and biggest moments of the night.