LuAnn de Lesseps entered rehab days before filming on "The Real Housewives of New York City," causing her to miss filming on the special taping with her co-stars. On August 23, as reported by Bravo's "The Daily Dish," de Lesseps took to her Instagram page and shared a message about her absence with her fans and followers, explaining that while she would have loved to reunite with her co-stars to hash out the events of Season 10, she knew her priority needed to be her health at that time.

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"Wish I could’ve been there but #HealthFirst #nevercountoutthecountess #rhony" she wrote in the caption of a photo of her Bravo co-stars. De Lesseps entered treatment for substance abuse issues in July and remained in treatment for a couple of weeks before returning home to New York City -- and to her cabaret show, "#CountessAndFriends."

During Wednesday's first part of the "Real Housewives of New York City" Season 10 reunion, host Andy Cohen mentioned LuAnn de Lesseps' absence and confirmed that she was seeking treatment.

“We’re concerned, but we’re glad [she] is being taken care of," he told her co-stars. "It is certainly not the same without [LuAnn] here," he continued. "We’re gonna discuss Luann’s journey a little bit later, but we still have an incredible season to talk about.”

LuAnn de Lesseps was arrested in December 2017

De Lesseps, who split from Tom D'Agostino in August of last year, was taken into custody in the wee hours of Christmas Eve morning last year after being found in a hotel room that didn't belong to her. During her arrest, the longtime reality star was accused of being violent with the responding officer before threatening to kill him. Weeks later, de Lesseps began her first stint in rehab.

While de Lesseps seemed to be doing well in the months that followed her first rehab stint of the year and even declared she was six-months sober in early July, rumors began swirling of a possible relapse around the time of her sobriety proclamation, and ultimately, she returned to rehab.

Bethenny Frankel was part of LuAnn de Lesseps' intervention

On Wednesday's episode, Bethenny Frankel revealed that she was part of a reunion staged for de Lesseps before the reality star returned to treatment for a weeks-long plan. There has been no word yet on who else was involved.

Tune in to the second part of the "Real Housewives of New York City" Season 10 reunion special [VIDEO] next Wednesday night, August 29, at 9PM on Bravo TV.