Hyderabad, Jan 29 : Actors Naga Chaitanya and Samantha Ruth Prabhu, who made their relationship official last year after being romantically involved for nearly three years, will get engaged later on Sunday.A source close to Chaitanya told IANS: "It s going to a very private affair and only the families of the couple and very close friends will be present. Even the venue has been kept a secret as they don t want public to come hoping to catch a glimpse of the couple."The event will take place at a plush hotel.Samantha s parents and her close friends from Chennai, where she grew up and studied, will be present."Samantha will be wearing a specially designed outfit by Kresha Bajaj. She s really excited about it," the source said.Chaitanya and Samantha first met on the sets of Gautham Vasudev Menon s Telugu romantic-drama "Ye Maaya Chesave" and went on to work together in films such as "Autonagar Surya" and "Manam".