What a hubby!

Prince William is stepping in for pregnant wife Kate Middleton, whose extreme morning sickness caused her to cancel a visit to Malta to commemorate 50 years of independence.

"The Duchess of Cambridge will no longer visit Malta this weekend. The Duke of Cambridge will undertake the visit instead #RoyalVisitMalta," the palace said in a statement.

"HRH continues to suffer from Hyperemesis Gravidarum. The decision was taken on the advice of doctors #RoyalVisitMalta."

The Duchess, 32, and The Duke, also 32, are expecting their second child together. They are already parents to baby George, who turned 1 year old this summer.

When Middleton's pregnancy was announced earlier this month, the palace said she was suffering from severe morning sickness, like she did with her first pregnancy.