"We're very pleased. They are happy and that is all that matters.
"As long as my children are happy, then I am happy.''
Ms Middleton shot to international stardom after appearing as her sister's bridesmaid in April 2011.
Named "her royal hotness'' by many UK media outlets, the fitness fanatic who in 2012 released her first party planning book, has attracted a global following with several social networking pages set up in her honour.
Mr Jackson, a Deutsche Bank employee, is reported to have been dating Ms Middleton for about six months.
"He is tall, good-looking and has the most amazing piercing blue eyes,'' a friend told the Daily Express.
"He is incredibly charismatic and stands out from the crowd. He is a really good catch. Everyone is after him.''
Ms Middleton used to date former England cricketer Alex Loudon, 32, a relationship believed to have ended about the time of the royal wedding.
- AAP