She was presented with a posy by 4-year-old Zac Barker, who, along with twin brother Oliver, plays Lady Mary’s son George.
In the hair and makeup department, Kate, 33, also met housekeeper Mrs. Hughes, played by Phyllis Logan, as she was made up by artist Nic Collins.
Also there? Robert James Collier, who plays the mean-spirited under-butler Thomas. He joked: “You’ve come just at the right time, Phyllis is about to have her Botox put in.”
Unfortunately, Dame Maggie Smith was missing from the joyous occasion as she was ill and couldn’t attend.
Kate’s visit followed her day out at the seaside Tuesday, when she went to an art gallery.
Friday will see her joining husband William, 32, and the rest of the senior members of the Royal Family paying tribute to those who served in Afghanistan, while next week the couple are heading to see the Irish Guards on St. Patrick’s Day before visiting the Brookhill Children’s Centre in Woolwich to learn more about the Home-Start charity and its support for children and families.