J Lo shared the official cover art Wednesday for "In the Morning," and it's a pretty simple concept -- an all-nude, provocative shot of the singer in a clever pose ... one that covers enough to keep it clean for the censors.

In case you've lost track, because Lopez has been doing this sort of thing for so long ... that's a 51-year-old sex symbol doing her thing.

J Lo started turning up the heat last weekend with her AMAs performance with Maluma -- just as she did with Shakira during the Super Bowl Halftime Show. The 'Morning' cover art makes for a great bookend on her 2020.

The single starts streaming on Black Friday, and until then ... expect Lopez to continue aging like a fine wine and looking amazing at all hours of the day.