Adele had a tearful interlude at her Vegas residency Saturday evening … when she noticed a fan in the viewers … and that will be Celine Dion.

Adele was singing “When We Were Young” at a packed area at the Colosseum at Caesars, when she eyeballed the well-known Canadian in the group.

Adele beelined it over to the “My Heart Will Go On” singer … the two embraced as Celine clasped Adele’s face. Tears flowed and Kleenex appeared.

It simply took a beat for all this to occur after which Adele obtained again to enterprise. But there was extra to come back.

Adele correctly intro’d Celine, and the group went wild, giving her a standing O.

As you realize, Celine’s been fighting Stiff Person’s Syndrome for a number of years and has pulled again on performing, though she made a triumphant return in the course of the Paris Olympics.