The 41-year-old actor announced Thursday on Instagram that his 36-year-old former "Ballers" co-star said "yes" to his proposal last week.
"Step by step, hand in hand, you & me, lock & key. #IAintNoFool #SheSaidYes #041417 #ItWasAREALLYGoodFriday #ForeverGrateful #WeGonRentTheMoonAndFillItWithRose #ILoveYouJaz," he captioned a series of photos.
The post shows Hill popping the question with an enormous diamond ring after taking Simon on a hot air balloon ride.
The couple celebrated afterward by posing for photos and drinking mimosas.
Hill and Simon co-starred as Larry Siefert and Julie Greane on the HBO series "Ballers."
The actress called Hill the "love of [her] life" during an interview with "Home & Family" on the Hallmark Channel in 2015.
"I met Dule at lunch," she recalled. "I was supposed to be in Miami for two days to shoot the 'Ballers' pilot and my two days turned into two weeks."
"I saw him, just me and him at the end of the table, and I was like, 'Oh, I know you. You're Dule!' And I went and we exchanged numbers and the rest is history," the star said.
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