The OG Queen of Vegas appeared on a special Sin City episode of Jimmy Kimmel Live!, filmed where else, in Vegas of course. Click the video to see Celine serenading Jimmy, talking about leaving Vegas after 16 (!) years, her favourite couch getting stolen, and appearing on the Deadpool movie.
She also performed Ashes, which was featured in the opening credits of Deadpool 2.
Source 1: https://www.youtube.com/watch?v=OwSWzOdUzFU
Source 2: https://www.youtube.com/watch?v=zF4f1_wBtVU