The beloved "9 to 5" singer got her first dose of the Moderna vaccine Tuesday at the Vanderbilt University Medical Center in Nashville, and shared a vid of the process, saying ... "Dolly gets a dose of her own medicine."

Clever headline, Dolly ... because as you may recall, she donated $1 million last year to coronavirus research, which she later learned was used to fund Moderna's vaccine.

The country music icon even changed the words to her famous song, "Jolene" ... busting out a hilarious -- and slightly dark -- parody version to hammer home her wish for everyone to get vaccinated.

Dolly's also playfully calling out the "cowards" and "chicken squats" afraid to get their shot by showing herself getting injected ... and she says it didn't even hurt.

As for why the 75-year-old waited so long to be vaccinated, she's previously stated she wanted to wait her turn. Dolly said, "I don’t want it to look like I’m jumping the line just because I donated money."