Joe Simpson is one proud papa. Make that, grandpapa. Jessica and Ashlee's dad sat down with ETonline to talk about his career move into photography, and revealed he recently took a very special snapshot.

"I got to take a picture of my little granddaughter the day she was born!" Joe gushed. This was the first time he's spoken publicly about Ashlee Simpson and Evan Ross' baby girl, Jagger, who was born on July 31. 

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"She's beautiful," Simpson continued. "She looks like her mommy 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." 

While Simpson wouldn't reveal the picture he took of little Jagger the day she was born, he did dish some more details about the big day.

"In the room with the baby, it was great to watch them have that moment," Simpson said of being there for the birth. "And, you know, grandparents, we were standing back... what a beautiful thing to watch."  

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Yes, Simpson said "grandparents." Evan Ross' mother, Diana Ross, was also in the delivery room! 

"She was there!" Simpson said. "Yeah, it was beautiful. 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." 

Simpson also grabbed some pics of Diana Ross with little Jagger -- but his focus isn't totally on family photos. Simpson is actually working a lot in the fashion space, specifically on editorials. In fact, he said he's set to shoot upcoming covers for Rolling Stone Russia and Flaunt Magazine.

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"I love fashion," Simpson said. "I love being able to shoot beautiful people ... It's just kinda like going back and finding a love that I used to have... it's brilliant." 

Simpson is juggling a lot these days. Along with new grandpa duties and the growing photography business, he's also launched his own fashion label, Control Sector.

"I love the opportunity to create and to do new things," Simpson said. "You know the photography thing is fun. The fashion thing is fun. I still do TV and I still do music, so you know, I'm crazy all the time ... I have plenty to do. I'm not bored!"

You can check out Simpson's work on his website or on Instagram. Fingers crossed a shot of baby Jagger pops up sometime soon.