Prince William and Kate Middleton
03/30/2005 AT 09:00 AM EST
Securing her position in the life of Prince William, beaming brunette Kate Middleton joined the young royal for his father Prince Charles's "stag week" in the Swiss Alps on Tuesday.
By Wednesday morn, the two – who met at St. Andrews University – were photographed as they hit the slopes in the drizzle of Klosters.
Charles, his sons and a group of friends are marking his last week of bachelorhood before the heir to the throne weds Camilla Parker Bowles on April 8.
The appearance of Middleton, 22, marked the second time in a week that the businessman's daughter was seen with her princely beau. Photogs snapped the couple leaving a London nightclub together on Monday.
Only last month, William treated her to another ski vacation in Verbier, Switzerland. The couple live together in a cottage on the outskirts of their university town in Scotland and are both are set to graduate this summer.
Middleton, however, will not be at the upcoming wedding, palace sources tell PEOPLE.