The unlikely trio were dining in the plush Princess Grace Suite and spent the entire evening together.
The former US President is in Dublin as part of a 48-hour tour during which he has a number of engagements in the North and Republic, and was joined by the two during his very brief trip.
And in the settings of the plush city centre haunt, it was only the best of the best all night.
The Princess Grace Suite is the hotel's elite presidential suite, consisting of two bedrooms and is the best room available at the five-star hotel.
Taking residence in the plush venue means the trio would have the luxury of space -- and wouldn't be short of any luxurious amenities at the hotel's disposal.
A well placed source explained: "The three of them had dinner and were together for a good bit of the night."
Clinton stunned evening shoppers by taking a stroll around St Stephen's Green yesterday.
The Shelbourne Hotel was in near lockdown as US secret service agents swarmed the area, which was also visited by former UK Prime Minister Blair.
A relaxed-looking Mr Clinton (64) was accompanied by around 30 security men during his evening tour around the capital.
He was shown a selection of buildings around the Green before going to Unicorn restaurant for dinner.
He stayed overnight at the Shelbourne Hotel where he was joined for a time by Mr Blair.
TV presenter Ryan Tubridy was also seen the hotel but an RTE spokesperson said he did not meet Mr Clinton.
Mr Tubridy has previously stated that the former US president would be among the guests he would most love to interview on The Late Late Show.