Kardashian gave birth to the couple's first child, daughter North West, in June.
A photo posted on Instagram shows a screen at the stadium that reads "PLEEEASE MARRY MEEE!!!" — in typical West font — above a black-clad orchestra. Another shows Kardashian showing off a diamond ring with a smiling West behind her.
The Kardashian clan has a series of reality shows on E!, but the network said Tuesday it did not have cameras at the stadium to capture the moment.
Khloe Kardashian seemed to celebrate on Twitter when she wrote: "Tears of JOY!!!!!!! Wow!!!!!!" She also tweeted: "Wow!!!!! Am I dreaming??!?!" Kimye were quiet on Twitter.
Kardashian was previously married to NBA player Kris Humphries. Their divorce was finalized in June after they were married for 72 days in 2011. Her first marriage was to music producer Damon Thomas in 2000.