They exchanged wedding vows in a traditional white wedding taking place at St Mary's Church in Bedfordshire's Woburn Abbey, reported BBC News.
The bride was stunning in a couture lace dress by Phillipa Lepley. A pair of vintage drop pearl earrings, a diamond necklace, a long veil, and a floral arrangement of pink, yellow, and white roses completed her look. The groom donned a three-piece suit.
The former Spice Girls star was accompanied by her daughter Bluebell. The little girl looked adorable wearing a white dress with a floral crown. Former bandmate Emma Bunton was among the guests.
Halliwell, 42, and Horner, 41, went public with their relationship in March 2014 and got engaged in November. He shares a daughter named Olivia with his former partner Beverley Allen.