The US rapper, who wrote a song called 'Wet' when the royal couple announced their engagement last year, said that he wished he could attend the nuptials on April 29 but is too busy.
Snoog Dogg told The Sun: "I got the invite but unfortunately I'm barbecuing that day so I won't be able to make it. I got a lot of love for my nephew William and I wish him and his beautiful wife the best of luck.
"Sorry I can't be there but my homey David Beckham gonna bring my present for the newlyweds."
Dame Helen Mirren recently revealed that she "feels" for Middleton because of the "stress" she must be under in the build-up to the wedding and joked that she had considered "bribing" people to get an invitation.
TV presenter Phillip Schofield admitted that he is "nervous" about being the anchorman for ITV's coverage of the ceremony.