Ashlee Simpson and Evan Ross are already "eagerly doting" on their newborn baby.

Evan Ross and Ashlee Simpson

Evan Ross and Ashlee Simpson

The couple - who also have Jagger, five, together - have been busy looking after Ziggy Blu Ross, who they welcomed into the world last week, and are "so happy" and "full of love" with their new arrival.

A source said: "Ashlee has been resting and spending time with Evan and her family since returning home with the baby. The two of them are so happy, full of love and eagerly doting on baby Ziggy. Ashlee's pregnancy was relatively easy. Ziggy arrived right on his expected due date, and free of any complications."

And Ashlee and her sister Jessica Simpson are most looking forward to their youngest children growing up together as Jessica's youngest daughter Birdie is only 18-months-old.

The insider added to E! News: "Some family has met the baby, however, everyone is being cautious because of COVID. Since Ziggy and Birdie's siblings are quite a few years older, Jessica and Ashlee are looking forward to the two of them growing up together."

Meanwhile, Ashlee and Evan previously revealed they take their kids with them everywhere.

Speaking before Ziggy was born, Evan said: “Even in the time that we’re working, we look at times where we can make sure we can get away and take trips with the family. We take [the kids] with us. I feel like that’s how I grew up.

“My mom used to take me everywhere. … We’d be running around doing the whole thing, so I feel like, why not?”

The 'Pieces Of Me' hitmaker previously said she is finding it hard being a "working mom."

She explained: "Music is a career by itself, having a clothing line is a career by itself, having a shoe line is a career by itself, being a mom is a career by itself. It's definitely overwhelming."