Ashlee Simpson’s father Joe is astounded by how “beautiful” her labour was.

The 30-year-old singer and her 26-year-old husband Evan Ross, the son of legendary songstress Diana Ross, welcomed their daughter Jagger on July 31.

And the birth was a family affair, as Evan, Diana and Joe were all present when little Jagger entered the world.

"In the room with the baby, it was great to watch them have that moment," Joe recalled to ET Online of what it was like being in the delivery room. "And, you know, grandparents, we were standing back... what a beautiful thing to watch."

Evan and Ashlee have largely kept away from the public spotlight in recent months due to their expanded family.

Patriarch Joe claims the couple are too enamoured with their newborn to be bothered with anything else.

"She's beautiful," the proud grandfather gushed. "She looks like her mummy and daddy ... Jagger is precious. She's quiet and sweet. She's just a happy baby ... and just, you know, the apple of her papa's eye."

Joe is convinced Evan will be a great dad.

He is impressed with how Love Hangover singer Diana raised him and his siblings.

“She's a wonderful person and, again, to see the love that she has for her children and now her grandchildren? It's a wonderful thing to see how Evan became so loving, because you gotta have a mom like that to make you that kind of person,” Joe noted.

This is a second child for Ashlee, who is already mother to six-year-old son Bronx with her ex-husband Pete Wentz.