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Hailey Baldwin and Justin Bieber

Justin Bieber and Hailey Baldwin are married, her uncle Alec Baldwin has confirmed.

The pop superstar and 21-year-old model Hailey sparked rumours they may have tied the knot in secret when they were seen leaving a registry office in New York last week. And while Hailey hit Twitter to deny the speculation, her actor relative Alec—brother of her father Stephen—let the cat out of the bag as he attended the 2018 Primetime Emmy Awards on Monday night.

"They just went off and got married," Alec told Access Hollywood on the red carpet of the Los Angeles event. "I don't know what the deal is."

The former 30 Rock star added that he's only met "Sorry" singer Justin once, but has some advice for newlywed Hailey considering his own happy marriage to wife Hilaria.

"We text Hailey every now and then," Alec continued. "We met him one time, but, as I said, you know when you get married ... it works best if you can really be together. Like, you hook your schedules up where you can really be with each other cause we make all of our decisions around."

However, Alec won't be talking to Justin about any advice he may want to share—as he wants to leave that up to Hailey's dad Stephen.

"She has a dad, and I'm sure he has a few paragraphs about that himself so I'm not worried (about giving Justin a talking to)," Alec smiled.

Justin and Hailey were overheard dropping several hints about a wedding as they visited the Marriage Bureau at the New York City Clerk's Office last week.

But Hailey insisted the fuss was all about nothing, taking to Twitter on Friday to write: "I understand where the speculation is coming from, but I'm not married yet."

The pair is currently in London, as Hailey debuted her first collection for Adidas at a catwalk show during London Fashion Week on Monday. The model was announced as the first ever "style creator" for Adidas and sportswear company JD back in July.