If you don’t think laughter is the best medicine, just ask Prince William.Despite a stressful week – which included a pregnancy announcement, hospital visits and more – the dad-to-be has managed to maintain his sense of humor.The Prince, making his first public appearance since wife Kate was released from King Edward VII hospital following a four-day stay with hyperemesis gravidarum (severe morning sickness), attended the Winter Whites Gala in London on Saturday.Michael O’Higgens, a former chairman of homeless charity Centrepoint, which the gala benefited, told reporters: "[William] said they shouldn’t call it morning sickness as it’s a day and all night sickness.”William was originally scheduled to attend the British Military Tournament at Earl’s Court in London on Sunday, but has canceled and will be spending the day "privately with the Duchess instead,” a spokesman for the couple, both 30, said in a statement to PEOPLE."It is well known that hyperemesis gravidarum often recurs and, until further notice, to allow the Duchess a degree of privacy during her pregnancy, we do not intend to offer regular condition checks or advise of routine developments associated with it,” the spokesman added.The couple’s next engagement is Wednesday December 12, when they are set to attend the royal premiere of The Hobbit movie in London’s West End.People