The latter star was spotted backstage lapping up the Believe singer’s performance.
In a video posted on Twitter, Dion is seen utterly engrossed in a screen backstage, singing along and bopping to the 71-year-old’s rendition.
Cher had received the Icon Award, and said on-stage: “I have wanted to do what I have wanted to do since I was four years old.
“I think luck has so much to do with my success. I think it was a little bit of luck and something else thrown in that had a little bit to do with my success.”
Dion also had a great night, after celebrating the 20-year anniversary of Titanic – for which she sang the monumental song My Heart Will Go On.
She had previously said of the invite to sing it at the bash: “This song means a lot to me, and it has played such a huge role in my career.
“I’m so grateful to the late James Horner, and to Will Jennings, for writing it and creating the opportunity for me to be part of Titanic, an amazing film whose legacy will continue for generations to come.”
The other big winner of the BBMAs was Drake, who picked up an astonishing 13 prizes.
As well as breaking Adele’s record for most triumphs, he also performed in the famous Fountains of Bellagio.
The Chainsmokers won four awards, while Beyonce and twenty one pilots won five each.
Miley Cyrus was also among the performers, and was introduced by sister Noah – who said she was appearing “for the first time in years with pants on.”