"I thought of absent friends and family; of Diana — but she’s with me all the time. What I miss most is her tinkling laughter," Ferguson said in an interview with Daily Mail.
"Diana was my best friend and the funniest person I knew. She had such timing and wit. It was a total joy to be with her because we just laughed and enjoyed life so much, and I know she would have loved the wedding."
Back in 2007, the Duchess of York revealed she and Diana were actually fourth cousins and that their relationship was similar to that of siblings.
"I really miss Diana. I loved her so much," Fergie told Harper's Bazaar at the time. "Diana was one of the quickest wits I knew; nobody made me laugh like her. But because we were like siblings — actually, we were fourth cousins and our mothers, who went to school together, were also best friends — we rowed."
Fergie said that "the saddest thing" was that the pair hadn't spoken for a year before Diana's death. "We hadn't spoken for a year, though I never knew the reason, except that once Diana got something in her head ... I tried, wrote letters, thinking whatever happened didn't matter, let's sort it out. And I knew she'd come back," she said.
"In fact, the day before she died she rang a friend of mine and said, 'Where's that Red? I want to talk to her,'" Fergie revealed.