The 31-year-old party planner was spotted at London's Heathrow Airport by young fan Grace Stroup, who saw her phone had an image of two-year-old George with his mother Kate, reports people.com.
Stroup tweeted: "I just saw the real Pippa Middleton in Heathrow airport and my god she's GORGEOUS."
Grace, 16, encountered Pippa when the socialite rushed past her on an escalator.
“She said thank you and was extremely nice, and then I did a double-take and instantly knew who it was. She pulled out her phone and her lock screen had a picture of George and Kate, smiling together looking just like a regular family - it was so cute,” she said.