Céline Dion's 4-month-old twins Eddy and Nelson were baptized in Las Vegas on Saturday, with 200 friends and family members in attendance, the singer's spokesperson confirms.

"It was a beautiful, traditional family ceremony," Dion's rep tells our friends over @PEOPLE of the Melkite Greek Catholic rite, which featured chanted prayers and songs and honored the heritage of Dion's husband and manager, Réne Angélil.

Five godparents stood up for the twins, who wore gowns by Baby Dior during the ceremony at St. Elizabeth Ann Seton Catholic Church: the twins' big brother Réne-Charles, 10; Dion's sister Linda; and Angélil's three oldest children, Patrick, Jean-Pierre and Anne-Marie Angélil.

Also on the guest list: the doctors who helped make Dion's dream of becoming a mother again come true, as well as those who treated Angélil's throat cancer more than a decade ago.

After the baptism, the twins napped while the family celebrated with a reception at Caesars Palace.

The following night, Dion, who launches her new Vegas show at Caesars on March 15, did her first practice run-through for a live audience.

Details of the baptism were first reported by the Las Vegas Review-Journal.