The Fashion Police presenter donned ripped jeans and an on-trend black and white jacket for the outing, and took to Instagram to share her day of family bonding with her fans.
"Pearl loves wearing #NannaKellys sunglasses!" wrote Kelly, alongside a too cute snapshot of the 17-month-old sitting in a swing.
Mother Lisa Stelly, who is married to Jack Osbourne, accompanied the duo on their day out and dressed her daughter in stripy leggings and a bright pink t-shirt. The adorable Pearl is pictured beaming at the camera, pointing to her aunt's gold, oversized shades.
A doting Kelly couldn't hide her pride and showed off more pictures of baby Pearl, calling her the most "perfect" member of the Osbourne clan.
"#OsbourneGirlsDayAtThePark lisaosbourne and the most #Perfect #beautiful member of our family Pearl!" wrote Kelly next to a photo of the smiling trio.
"Nothing better than spending time with Pearl at the park!" wrote the 28-year-old star again, alongside a snapshot of Kelly holding Pearl tightly to her chest as the pair ride down a slide. The lilac hair coloured presenter embraced the outdoor activity and went barefoot down the ride.
Lisa and Pearl's outing to the park comes weeks after the mother-of-one announced the tragic news that she and husband Jack had lost their unborn baby.
The couple have put on their bravest faces and took little Pearl on a fun trip to Disneyland California at the end of September, just a few weeks after Lisa's late-term miscarriage. The trio looked to be in high spirits, and Jack was clearly enjoying spending quality time with his family and taking a break from his Dancing With The Stars training regime.
Jack decided to take part in the show to help raise awareness of Multiple Sclerosis following his diagnosis in 2012. "Right now I'm physically able to do DWTS but it might not always be this way, so I don't want to miss this opportunity," he said.
When asked how he was feeling about being on the show, Jack modestly replied, "We all have our personal problems to overcome."