Lifestyle Style Jessica Simpson Pens Love Letter to Herself in Honor of 42nd Birthday: 'I Know My Purpose' Simpson, whose birthday falls on July 10, wrote a powerful caption dedicated to herself alongside a stunning photo of her on Instagram Monday By BreAnna Bell BreAnna Bell Digital News Writer, PEOPLE People Editorial Guidelines Published on July 12, 2022 12:09 AM Share Tweet Pin Email Photo: jessicasimpson/Instagram Jessica Simpson is ready to "rock 'n' roll" into 42! The fashion designer, who was sporting a knee-length black cutout dress and strappy stilettos while basking in the glow of the moon in a picture posted to Instagram Monday, penned a powerful and inspiring message to herself in honor of her birthday, which falls on July 10. "Oh lil Mrs 42 look at you leanin' into the moonbeams to recharge and radiate a purposeful glowing heart," she began the caption. Jessica Simpson Shares Makeup-Free Selfie with Reflection on Father's Day: 'Just Woke up Feeling Grateful' jessica simpson/instagram "I am very proud of my faith, resilience and strength over the last 4 decades. Everything in my life that has or hasn't happened yet makes turning 42 very exciting because I know what it takes personally to remain inside of DETERMINED PATIENCE," she continued. "I know myself and I do love her very much. I know my purpose and I must say that ladies and gents I am equipped to waltz within every dream I own confidently. I am humbled and honored to finally be my own best friend. Ok ✨42✨ time to Rock 'n' Roll," the Open Book author concluded. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. The Employee of the Month actress also gave fans an inside look at her big birthday celebration, posting a slew of photos with friends and family – including husband Eric Johnson, and parents Tina and Joe Simpson – on her Instagram Story. Simpson capped the night off by blowing out a sparkler candle on her elegantly simple green birthday cake. Jessica Simpson Shares Cute Photo of Daughter Maxwell and BFF North West from 'Camp North' Trip jessica simpson/instagram The weekend birthday festivities continued Monday, as the "Take My Breath Away" singer revealed she received a box of donuts spelling out "HBD Mom" from Blinkies Donuts, as well as a special gift from her son, Ace. The 9-year-old created a makeshift robot costume for his mother out of cardboard boxes and packaging foam. He also wrote a note for her on the front: "Best mom ever in the world. I love you so much." Simpson also shares two other children –– daughters Maxwell, 10, and Birdie Mae, 3 –– with Johnson, whom she wed in 2014. RELATED VIDEO: Jessica Simpson's Daughter Maxwell, 9, Is All Grown Up in Snaps from Sister Birdie's Barbie Party Earlier this month, the singer shared that she and her family "had the best 4th of July week" taking a trip to visit their cousins in Lake Austin for the holiday. "We asked the kids where they wanted to go for their summer trip and out of everywhere, they chose Texas to be with their cousins," she shared. "It was a sentimental and nostalgic blast of a week." "Settled into summer feeling good," she concluded.