On Monday, the world received some wonderful news: Britney Spears is pregnant.

She dropped the announcement very casually on social media.

That's how the rest of us learned about Britney and Sam Asghari's happy news. But what about those closest to her?

Britney's sons are both teens, and they were the first people who found out that they're going to be big brothers.

HollywoodLife reports that Britney Spears made sure that 16-year-old Sean Preston and 15-year-old Jayden James were the first to know.

The boys, whom she shares with ex-husband Kevin Federline, are said to be very excited about the news.

Britney is eager for them to get to meet their little sibling. Sean and Jayden are just happy for their mom.

“Britney’s sons could not be more thrilled right now about her pregnancy," an insider described.

"She told them first," the source revealed.

The insider explained that Britney did this "as she knew how much this would affect their lives."

"This baby is going to have some awesome big brothers," the source expressed.

"And," the insider affirmed, "Sean and Jayden will most definitely be a part of this child’s life."

The boys are a year apart, so it's safe to say that not even Sean has had a "big brother" experience like they're going to.

This will also be a huge change for Britney, even though she is no stranger to having a kid.

“With Sean and Jayden," the insider recalled, "she was stripped of the right to have this experience."

The source explained: "In the first part of their lives, she was still focused on her career and had very little time for herself."

"When they were 2-3, she was placed into conservatorship," the insider noted.

"And," the source lamented, "she never got to have the firsts that many mothers do with their kids."

The insider detailed that this was "because, after that, she always had to have someone else present, or have monitored visitation."

This will be so different for Britney, and she has learned -- and unlearned -- a lot.

We're talking about a woman who grew up thinking that it was normal for parents to use liquor to "help" their children sleep.

Instead, she learned to be a better parent to her children than hers were ... and admittedly low bar ... and won over fans and former critics with her parenting.

“Britney is so thankful that she finally gets to have the experience of raising a baby," the source noted.

The insider expressed that this is something "that she has always dreamt of her whole life."

The source acknowledged: "There was a point where she didn’t think this would ever happen."

Kevin Federline addressed Britney's pregnancy announcement through his attorney, as has been his public relations practice for years now.

He offered his congratulations, and also praised Britney as a parent.

Who would know better than Kevin, Sean, and Jayden how lucky this future child will be to grow up with Britney as a mom?