The engagement ceremony of Nazifuddin Najib and the 25-year-old Fitri was held at a hotel in Jakarta on May 4.
It is understood that the couple plans to wed in December.
Fitri is the daughter of prominent Indonesian businessman Tommy Sumardi.
Nazifuddin, 32, is one of three children from Najib’s previous marriage with Tengku Puteri Zainah Tengku Eskandar.
Tengku Puteri Zainah’s name was mentioned alongside Najib’s in the invitation card.
Najib and his wife Rosmah Mansor, who have been under a travel ban imposed since his fall from power last year, did not attend the function.