While the prince is patron of the WRU, the princess holds a similar position with the Rugby Football Union (RFU).
The couple have previously joked about supporting different teams during the tournament, with the prince supporting Wales and Catherine rooting for England.
In 2023, the prince remarked that it would be a “tense journey home” with his wife after a Six Nations game between the two countries in Cardiff.
Wales have not won a Six Nations game since beating Italy in March 2023, a losing streak that stretches to 15 games despite a determined display against Ireland last week.
Italy meanwhile will travel to the Principality Stadium in high spirits after a historic first win against England in Rome last Saturday.