Princess Kate can’t get enough of a Self-Portrait blazer dress , and she once again showed her allegiance to the brand at a royal garden party on Friday, May 8. The Princess of Wales joined Prince William , Duchess Sophie, Prince Edward and Zara and Mike Tindall at Buckingham Palace to mark the second garden party of the season, and Kate brought out all the fashion stops in a polka dot outfit. The princess wore a vintage-inspired cream dress featuring a wool jacket with a 3-D satin rose, but hers featured some different details than the $750 style available for sale. Self-Portrait's original dress has a full satin skirt, but Kate's appears to be a custom version with a slimmer, longer pleated skirt. The royal further customized her outfit with a different belt, and swapped out the black one that comes with the dress for a white style. Princess Kate is pictured at a Buckingham Palace garden party on May 8. (Image credit: Getty Images) Princess Kate is pictured at a Buckingham Palace garden party on May 8.…