Katy Perry invited Duke and Duchess to party

Katy Perry invited Britain's Duke and Duchess of Cambridge to her concert in Ottawa on Sunday (03.07.11) - but they did not accept the offer.

Katy Perry invited Britain's Duke and Duchess of Cambridge to her concert at the weekend.

The 26-year-old singer - who is married to British comic Russell Brand - began the Canadian leg of her 'California Dreams' tour last week and was thrilled when she realised the royal couple were going to be in the same city as her on Sunday (03.07.11).

Referring to the Alexander McQueen gown Catherine wore to her wedding in April, Katy tweeted: "In OTTAWA! Heard Prince William & Kate are here, come to the show!!! (Kate- bring the Mcqueen!) (sic)"

The royal couple - who already have a full schedule of activities for their North American tour - failed to accept the invitation.

This isn't the first time the 'California Gurls' hitmaker has revealed her love for the royal couple.

When they married on April 29 in London's Westminster Abbey, Katy showed her appreciation by getting a special manicure featuring different images of William and Catherine on each of her fingernails.

She posted a picture of the results with an accompanying tweet reading: "In honor of the Royal Wedding, I present you... My royal NAILS! CONGRATS (sic)."