That wasn't the only costume the 40-year-old actress tried on for her fans. Witherspoon also modeled her bunny suit and several pink ensembles, in addition to reciting lines from the movie on both her Snapchat and Instagram.
"Whoever said orange is the new pink was seriously disturbed," she recited while dressed as her beloved character.
The mother of three also tried on the dress Elle wore when she had her date with Warren and thought he was going to propose.
After a big day going down memory lane, Witherspoon had a message for her followers. "Wow, what a day!!!! Thank you all so much for celebrating 15 years of #LegallyBlonde with me. I had a blast! #LegallyBlonde15," she Instagrammed.
In celebration of the beloved comedy's anniversary, ET found our interview with Witherspoon when she talked about Legally Blonde when she just 24 years old. "The whole movie is sort of a play on 'dumb blondes' and how when a person looks a certain way, you perceive them as being sort of stupid," she told ET on set in 2000.