"Opposites attract," "Equal and equals like to join," and there are probably still a lot of gradations in between: there are different theories when it comes to how similar couples should be. Justin Bieber and Hailey Baldwin seem to be clearly on one side of the spectrum - at least that's what Ireland Baldwin says.

"They are perfect for each other because they are like the same person," said the 23-year-old "People" about her cousin and her partner. The two would go through difficult times together: "I feel like they are going through the same fights and that they are just helping each other," Ireland Baldwin said.

Ireland Baldwin works as well as her cousin as a model. She is the daughter of former actor couple Kim Basinger and Alec Baldwin. They divorced in 2002.

Justin Bieber and Hailey Baldwin have been officially engaged for several months. However, Baldwin's uncle, Alec Baldwin, told reporters at the Emmy Awards last September that the couple had already married.

The 22-year-old had previously denied this. Weeks later, Baldwin changed her name to Instagram: where she is now called Hailey Bieber and no longer Hailey Baldwin. Even Justin Bieber had already described her in a message as a wife.