Dressed up in a glam black outfit, Cyrus donned a curly blonde wig and applied lipstick while looking in the mirror in one Boomerang.
In another, she pouted and gave her upper body a shake for the camera.
The clips were likely taken during a 2017 appearance on The Tonight Show Starring Jimmy Fallon, during which Cyrus dressed up as Parton and Fallon channeled Kenny Rogers as the two recreated the country stars’ duet, “Islands in the Stream.”
Cyrus also posted a snippet of that performance, alongside one of Parton and Rodgers performing the same track together.“Happy Birthday Aunt Dolly!!!!! ( . ) ( . ) @dollyparton,” Cyrus captioned the post.
Actress Hilary Swank then commented, “Your voice is absolutely stunning ?.”
Cyrus also posted photos of her and Parton on her Instagram Stories, writing, “Happy birthday to the woman who taught me how to glue down a lace front …. I’ll love you forever Aunt Dolly @dollyparton!!!!!!!”
Meanwhile, Julianne Hough, who worked with Parton in Dolly Parton's Heartstrings, also paid tribute the singer on social media.
”Happy Birthday to this queen butterfly ?,” Hough captioned a cute candid snap of the two on Instagram. “Thank you for leading by example and reminding us all to dream big and that anything and everything is possible! I will always love you ?.”
Pee-wee Herman also posted a fun photo with the country queen.
“HAPPY BIRTHDAY to the one and only Dolly Parton!!!” he wrote. “This photo is from 1987 when she was on Pee-wee's Playhouse... through The Dolly Show! 1987! We sang "Hey, Good Lookin'" together! #happybirthday #dollyparton.”