But Richie is planning to fix that in short order.
"I've been on the road. I just got home, and so it's really going to be now that's the time for me to sit down and think about what I want," Richie says in an interview set to air Tuesday on The Ellen DeGeneres Show.
Asked if they've set a date for the nuptials, she replies: "Not yet, but soon."
Richie, 28, and Madden, who turns 31 on Thursday, confirmed their engagement in February, with Richie saying it took becoming a mom for her to realize she was ready to be a wife.
The couple have two kids: daughter Harlow, 2, and son Sparrow, 6 months.
Richie, whose father is the legendary singer-songwriter Lionel Richie, also reveals to DeGeneres that she was in a rap group when she was 8 years old – and, after some coaxing, performs a rap for Tuesday's broadcast.