Sarah Ferguson insists her daughter Princess Eugenie is not engaged.

Sarah Ferguson

Sarah Ferguson

Despite reports that 26-year-old Eugenie's long-term boyfriend Jack Brooksbank, 29, has popped the question after six years of dating, her mother Sarah says the pair are not planning to wed just yet.

When asked by PEOPLE if they are engaged, Sarah laughed and said: "No."

However, sources close to the royal family are full of praise for Jack.

An insider said: "He is a really lovely chap. They adore each other and are really serious."

Meanwhile, Sarah has spoken about how proud she is of her daughters.

She said: "My daughters are the finest ambassadors of good parenting from Andrew and I.

"Beatrice just raised a great deal of money for her charity Big Change, doing a Strive Challenge with the Bransons. And then she went with the Franks Foundation to eye hospitals in Nepal. And she has scoliosis of the spine and she does an awful lot for orthopaedic research. They are very extraordinary girls."

Eugenie and Jack reportedly flew to Queen Elizabeth's home in Scotland last month to ask for her blessing on their forthcoming engagement.

The loved-up couple spent two days at the monarch's Balmoral Castle because Eugenie's cousin Prince Harry was hosting a shooting party to celebrate his 32nd birthday, but it's believed Jack took advantage of the time by asking his lover's famous grandmother for her approval.

An insider at the castle said: "You could call this weekend a rite of passage for Jack. There is no way he would be invited to stay with the Queen unless he was being welcomed into the royal fold and the bosom of the family."

However, a friend of Jack admitted that he was riddled with nerves ahead of his visit to Balmoral.

The pal explained: "You could say he was somewhat apprehensive about going to Balmoral. But Jack has no side to him and will just be himself."