Earlier, Charles was seen arriving at Lagos Airport in Nigeria without his wife as he embarked on the final day of his eight-day tour.
A palace insider told the UK’s Express that Camilla’s early departure was because the Duchess “doesn’t want to take too much on”.
It is well-known that Camilla dislikes flying.
But Charles – who is about to celebrate his 70th birthday - appeared at ease as he attended the glittering engagement with Naomi, 49.
The former supermodel wore a black velvet Ralph & Russo velvet dress with a feather trim.
“Firstly I would like to wish him a Happy Birthday. He looks amazing. He doesn’t look his age, his spirit is young. I told him that his spirit was young,” Naomi said.