Celine Dion fought back tears as she returned to Las Vegas to do her show ... just 2 days after the carnage on the Las Vegas Strip.

The singer offered concertgoers at Caesars Palace Tuesday night words of comfort, while admitting it was a difficult decision about whether to even go on with the show.

Then she made an emotional announcement about how she, and her fans, will assist the families of the victims from Sunday's shooting that killed 59 people and injured more than 500.

Gotta imagine ... not a dry eye in the house after this message from Celine.