Police were called, but the couple left after the ring could not be found. Police found the ring early the next morning.
The emergency services were unable to find it and the would-be bride and groom gave up.
It wasn't a complete disaster, however, as the woman said yes before the ring fell through the grate and plummeted eight feet below their feet.
The department has taken to social media in an effort to enlist the public's help in locating the couple.
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The NYPD's official Twitter feed posted a photo of the ring.
"WANTED for dropping his fiancée's ring in @TimesSquareNYC!"
The only problem: The NYPD is still searching for the couple.
'If anyone can find this (un) lucky couple, it's New Yorkers and the millions who visit Times Square'.