Madonna and son David, in 2007
Karel Prinsloo/AP
Shireen Ritchie spoke on Britain's GMTV program, which was highlighting the plight of orphaned children.
Madonna is in the process of adopting a Malawian boy, David Banda, after his father placed him in an orphanage in October 2006 following the death of his mother.
Interviewer Fiona Phillips asked: "You have probably one of the most famous adopted little grandsons in the whole world now. How's that all working out?"
"It's working out very well," Ritchie replied. "They're wonderful and loving parents and he's a very lucky little boy."
