Addison's last name isn't Rae — it's actually Easterling, which is the same last name as her mother's. Her father, however, has the last name Lopez, as do her younger brothers.

While no one in Addison's family has commented on the difference in their last names, it likely has something to do with when Addison was born. Sheri and Monty are only in their early 40s, while Addison recently turned 20. If you do the math, that means Sheri and Monty had Addison while they were still young — think their early 20s.

It's unclear when exactly Sheri and Monty married, though it's speculated to be sometime after they had Addison. This theory is supported by this video posted to Monty's Instagram account. In what looks like a chronological timeline of his family, Monty shares a photo of him and Sheri while they're really young, followed immediately by a photo of them with Addison as a baby, and then a wedding photo before introducing photos of Addison's brothers.

If the photos are in chronological order like they appear to be, then it would likely explain why Addison's last name is Easterling instead of Lopez, and why her brothers' last names are Lopez.

The age gap between her and her brothers could also have something to do with it, as both of Addison's brothers are considerably younger than her.