The Daily Telegraph said Middleton will attend Saturday's royal wedding alone, while her boyfriend heads to Kenya for a close friend's wedding.

The decision to have Middleton stand in for the prince at a royal event is fueling speculation that an engagement between Middleton and William is imminent, the newspaper said.

Clarence House declined to comment on the scheduling of the two events but a senior royal source told The Telegraph the prince's family isn't upset with him for missing the wedding of his cousin.

"Prince William is going to be out of the country this weekend on a long-standing prior engagement," the source said. "It is an unfortunate clash but he spoke to his cousin Peter and he is fine with the situation. His girlfriend will be going in his absence."