The royal couple exchanged vows on Saturday, confirming that they loved each other and that lobola had been paid in full.
About 10 000 people, including President Jacob Zuma, Inkatha Freedom Party presidentMangosuthu Buthelezi and the royal families of Zululand and Swaziland, turned out for the wedding.
Mafu, 27, joined the royal family 10 years ago at the age of 17, but the traditional ceremony was only completed today.
Zwelithini and his bride were dressed in traditional attire, as were Zuma, Buthelezi and the thousands of members of the traditional Zulu regiment who participated in the festivities.
Sunday will mark the final leg of the three-day wedding, in which prescribed gifts are exchanged ahead of a thanksgiving feast.