The royal babies, named Jacques Honoré Rainier and Gabriella Thérèse Marie were delivered by Caesarean at Princess Grace Hospital on Wednesday afternoon.
A statement released from the Palace read: "It is with immense joy that TT.SS.HH the Prince and Princess of Monaco have the great pleasure to announce the birth of their children named: Gabriella, Thérèse, Marie (born at 17h04) Jacques, Honoré, Rainier (born at 17h06)."The births took place on 10th December 2014 at the Maternity of the Princess Grace Hospital Monaco. The Princess and the children are doing well."
The statement also read that "The Prince Jacques, Honoré, Rainier is the Crown Prince.
"In accordance with the historic custom established by the treaty of Péronne (1641), He shall receive the title of Marquis of Baux (in Provence).
"The Princess Gabriella, Thérèse, Marie, second child in the line of succession, shall receive the title of Countess of Carladès (in Auvergne)."
A former South African Olympic swimmer, Charlene, 36, married Prince Albert, 56, in 2011.
The royals announced that Princess Charlene was pregnant in May. Prince Albert has two other children from previous relationships.