The 30-year-old model has taken to her Instagram account to heap praise on the Compton-born beauty, saying she's proud of Danielle for helping break down boundaries by becoming only the third black woman to appear on the cover of the iconic magazine.
Alongside a photograph of the cover, Ashley wrote: ''DANIELLE!!!! Tears of joy for you this morning! Congratulations on breaking even MORE barriers being the 3rd black woman to ever grace the cover of @si_swimsuit! I have so many emotions SOAR BABY GIRL!! @danielle_herrington_ (sic)''
Tyra Banks and singer Beyonce are the only other black stars who have appeared on the front cover of the magazine.
Meanwhile, Ashley has also been credited with breaking down boundaries within the fashion industry, becoming one of the world's best-known plus-size models.
And the brunette beauty recently revealed that her mother Linda has been a central figure in her career, giving her the confidence she needed to pursue her ambitions.
She shared: ''My mom has been my role model since childhood and has played a vital role in developing my confidence. She promoted body positivity in our household before it was a movement.''
Ashley and Linda have similarly curvy figures, and Ashley previously admitted to feeling inspired by her mother's self-assured outlook.
Of her influence, she said: ''Her feel-good attitude toward her own body has shaped my ability to remain positive and self-assured.''
Janelle Monáe parties and drives with her girl squad in the video for her latest single 'Crazy, Classic, Life', taken from her album 'Dirty...
Continuing the softer sound of their 2015 release 'That's the Spirit', BMTH are about to release 'Amo' (January 25th 2019) featuring their newest...
To coincide with the new BBC mini-series adaptation of leporine epic Watership Down, Sam Smith has unveiled a new single entitled 'Fire on Fire'.
Her first single since leaving the jungle on 'I'm a Celebrity... Get Me Out of Here!', Fleur East drops the super-choreographed video for 'Favourite...
Dropping the video for his latest album's second single, 'Excuses', is Olly Murs just months after the release of 'Moves' featuring Snoop Dogg.
Professor Green and Rag'n'Bone Man have teamed up for a heart-wrenching video for their single 'Photographs'.
He released 'Everythang's Corrupt' last month, and now Ice Cube has dropped a video for the record's third single 'That New Funkadelic'.
Dappy has unveiled a new stripped down number entitled 'Count On Me' more than six years after the release of his debut solo album.