The pair became engaged in South Africa on the season finale of the ABC romance reality show on Monday night, after Brad chose Emily over fellow finalist Chantal O'Brien.
"Congratulations Brad and Emily. I wish you two all the happiness in the world and a beautiful life together," wrote Girardi on her Twitter account.
The 26-year-old appeared on the previous season of The Bachelor, where she was chosen by airline pilot Jake Pavelka. They became engaged in the Caribbean on the season finale, which was broadcast in March 2010, but announced their separation the following June.
Girardi is now dating former Bachelorette contestant Kasey Kahl, who appeared on Ali Fedotowsky's season of the ABC franchise last year.
Fedotowsky, who appeared alongside Girardi on Pavelka's run of The Bachelor, also offered her congratulations on Twitter after the show, writing: "I really hope Brad and Emily have a long, happy life together!"
The Bachelorette returns to ABC on May 23.
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