Duchess Catherine helped open the new Mittal Children's Medical Centre at Great Ormond Street Hospital on Wednesday morning (17.01.18).

Duchess Catherine

Duchess Catherine

The 36-year-old royal - who is pregnant with her third child with husband Prince William - was greeted by nine-year-old patient Ava at the children's hospital in London, and spent time with the poorly youngsters who were busy with art activities.

A series of tweets by Kensington Palace revealed: "The Duchess of Cambridge is welcomed to @GreatOrmondSt (GOSH) by 9 year-old patient, Ava.

Today HRH is opening the new Mittal Children's Medical Centre, which will enable the hospital provide world-class care to even more children ... The Duchess joins some children for an art activity, and discovers more about the positive impact the new centre is having on @GreatOrmondSt patients & their families (sic)"

With the new facility up and running, the children being treated will be able to have their parents/guardians stay over with them.

The palace added: "The children have been able to move into new, modern wards where parents or carers can stay comfortably overnight by their child's bedside. (sic)"

Catherine - who has four-year-old Prince George and Princess Charlotte, two, with William - follows in the footsteps of the late Queen Victoria and her grandmother-in-law, Queen Elizabeth - both patrons of Great Ormond Street - by paying a visit to the hospital.

Revealing GOSH's history with the royals, the palace shared: "The Royal Family has a longstanding connection with GOSH; Queen Victoria was the hospital's first Patron after its foundation 1852.

The Queen is the current Patron and has visited a number of times during her reign. (sic)"

Later today, Catherine - who is a patron of the All England Lawn Tennis and Croquet Club - is due to visit Bond Primary School in Mitcham, south London to learn about the Wimbledon Junior Tennis Initiative, which offers free coaching to young people.