The model and the "Sorry" singer sparked speculation they had tied the knot when they were pictured visiting the Marriage Bureau at the New York City Clerk's Office earlier this month. Hailey went on to deny the claims, but then her uncle Alec Baldwin caused confusion when he told reporters they were married.
Alec's model daughter Ireland has now weighed in, telling Entertainment Tonight that she doesn't know the full story, but doesn't think they would rush into marriage only two months after their engagement.
"I have no idea what their situation is," she said. "I think they're just taking things slow. They're just kissing all over the world. They're just kissing and loving and having fun, and I think people take little details and get too caught up in them, and they're looking too hard."
She made similar comments to Extratv.com, saying, "Honestly I don't think so - I think they were getting things sorted and think people are reading into photos and things way too deep - they are 'Da Vinci Code'-ing something that's not happening."
Hailey, 21, and Justin, 24, reconciled earlier this year after previously dating in 2015, and Ireland believes their engagement has been on the cards for a while.
"It was meant to be a long time ago," she told ET. "It was just a long time coming, and we're all like, 'Alright, thank God, let's move forward.' They're so in love and they really do a lot of good for each other, and that's the most important thing for me, that he makes her so happy."
She added that they have been through "a lot of trial and error as individuals and together" and have "proved" they're each other's soulmates.
The couple, who have recently been spotted in London and enjoying a vacation in Italy, reportedly made the trip to the Marriage Bureau to obtain a marriage licence and are said to be in the process of negotiating a prenuptial agreement.