August Jr. belongs to Germany's now-deposed royal family.
Held in Hanover on Saturday, his wedding marks the first time a Hanoverian prince marries in the city's historic Market Church in 66 years.
Malysheva wore three custom-made gowns at the festivities; all designed by Mansour - a long time friend of the bride.
“I always knew Sandra would design my wedding gown,” Malysheva told Vogue Magazine.
“All three gowns were inspired by my Russian heritage and had a very ethereal, romantic feeling,” the bride added.
The "Royal" Dress
"Embellished with elaborate beaded details"
A closer look
The pre-wedding gown
A rising Lebanese star in the world of fashion
Mansour was born and raised in Switzerland.
Working with Saab, Mansour "received first-hand experience with fabrics, textiles, embroidery, prints and cuts."
She has now become well known "for her tasteful embellishments like hand-placed sequins, beading, and embroidery," Vogue wrote.