Nicolas will be christened in the royal chapel of Drottningholm Palace - the same place that Nicolas' big sister Princess Leonore was also baptised in June 2014. The service is confirmed to be broadcast on Swedish television.
Princess Madeleine and Chris O'Neill's son will be baptised on 11 October
After the religious ceremony Nicolas' grandparents King Carl XVI Gustaf and Queen Silvia will host a reception at the Palace, with guests likely to include Prince Carl Philip and his wife Princess Sofia, as well as mother-to-be Crown Princess Victoria and Prince Daniel with their daughter Princess Estelle.
No further details have been released about the christening as yet, but it is expected that Nicolas will be baptised in the same gown as King Carl XVI Gustaf, Princess Victoria, his cousin Estelle and his big sister Leonore. It has not yet been revealed who will be named godparents to the baby prince, who will be four months old when he is christened.
Prince Nicolas of Sweden was born on 15 June
Prince Nicolas was born on 15 June at the Danderyd Hospital, and is currently sixth-in-line to the Swedish throne. Since his birth the baby boy and his family have relocated to London, with Madeleine's businessman husband telling Swedish newspaper Expressen that they would be making the city their permanent base for two years.
"We always planned on moving to London but then the baby was born and we thought it would be a good idea to stay in Stockholm for a bit," Chris explained. "I don't want to be alone in my hotel room every night. I want to go home to my family and have dinner together. Nothing else matters more."
Chris and Madeleine married in June 2013 in Stockholm. The couple welcomed their first child Leonore in February 2014, and ten months later it was announced that Madeleine was pregnant again, with baby Nicolas joining the family in June 2015.