Some Christian religions and sects uphold the belief that the Lord Jesus Christ is a man-God (or a God-man), a true God and true man at the same time. One of those Christian religions and sects which uphold this belief is the dominant and powerful Roman Catholic Church.
464 The unique and altogether singular event of the Incarnation of the Son of God does not mean that Jesus Christ is part God and part man, nor does it imply that he is the result of a confused mixture of the divine and the human. He became truly man while remaining truly God. Jesus Christ is true God and true man.
Source: Catechism of the Catholic Church