The couple tied the knot in front of friends and family over the weekend, with Ashlee's newlywed sister Jessica Simpson serving as matron of honour as the bride's niece Maxwell, two, and nephew Ace, 14 months, took on the roles of flower girl and ring bearer, respectively.
Ashlee's own son, five-year-old Bronx Mowgli, with her rocker ex Pete Wentz, walked his mum down the aisle.
Further details about the ceremony have since emerged, with Ross presiding over the nuptials herself and later treating the wedding party to a rare performance of her 1981 hit Endless Love.
A source tells People.com, "When Diana got up to sing at the reception, she surprised everyone, even her kids! She was the only one on the dance floor and everyone rushed to see her."
Ross wasn't the only celebrity wedding officiant this weekend (30-31Aug14) - actress Essence Atkins also helped to marry her best pal Gabrielle Union and her new husband, basketball star Dwyane Wade, at a lavish ceremony in Miami, Florida.