Several suggested it may have been all a ploy to plug her dating show, Love Hotel, with one joking she may have indeed met someone on the series.
'The marketing budget for the Love Hotel is wild,' one wrote.
'LOVE HOTEL GUY??' another asked with several laughing-crying emojis.
One Instagram user joked de Lessops may have been attempting to one-up fellow RHONY alum Bethenny Frankel.
'Bethany is getting too much attention for her liking,' they mused, nodding to Frankel's recent runway walk for Sports Illustrated in Miami.
At this time, The Daily Mail has not received a response to its request for comment.
Regardless of whether she is engaged, the mother-of-two does appear to be in a relationship with a hunky mystery man.
While in the Hamptons with her lover on Friday, the lovebirds were seen sharing a passionate kiss as they picked up their mail.
Although his identify remains unknown, the good-looking and tall guy appeared smitten as he grabbed his arms around her.
It is unknown who de Lesseps is dating at this time, or if she simply bought the ring for herself and it is not an engagement ring at all.
In February, de Lesseps revealed to reporter Derek Zagami that she went on a date with a 62-year-old model.
'He continues to model to this day, does very well, is the salt-and-pepper gray,' de Lesseps said.
The reality star described the man who she went out as a 'husband commercial type of guy, but very nice.'
Before that date, the Berlin, Connecticut-born celebrity was linked with Southern Hospitality personality Bradley, 28.
In January, an insider told Us Weekly that the pair appeared to be cozy while spending time with one another at New York City's Dream Hotel.
The two were 'all over each other,' a source said, after a January 24 Watch What Happens Live taping.
The next month, she addressed the night out with her fellow Bravolebrity while speaking to TMZ.
'We definitely had great chemistry and we went out to have drinks - what's wrong with that?' she told the outlet.
de Lesseps then acknowledged that Bradley had 'a girlfriend' but would date him if they broke up.
'Hell yeah! Are you kidding me? Well, I'm a little bit of a cougar, let's put it that way,' she admitted.
Bradley addressed his relationship with de Lesseps during the Southern Hospitality reunion episode for season two, saying that there was chemistry between them, but no physical intimacy.
'This is the truth - me and Luann got a drink, and we hit it off,' Bradley said. 'I did cross a line at the hotel, but I did not kiss her. We did not hook up.'
Bradley conceded he 'probably was too flirtatious' with the Big Apple socialite.
Previously, de Lesseps was married to Count Alexandre de Lesseps.
During their marriage they welcomed their two children, Noel and Victoria.
She was also briefly married to Tom D’Agostino Jr. between 2016 to 2017.
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