Pippa, who is the sister of the British royal Kate Middleton, got married last year to the former British racing driver James Matthews and the couple recently gave birth to their baby son Arthur.
The 35-year-old looked chic in a camel coat and black turtleneck as she was seen leaving the department store.
Pippa and James welcomed Arthur on October 15 but only revealed his name a few days afterwards.
His full name Arthur Michael William is a tribute to Kate and Pippa’s father and her husband’s younger brother who died tragically while climbing Mount Everest.
Pippa has got back into shape extremely quickly after giving birth thanks to her exercise regime, but revealed she had to give up one of her favourite workouts.
'I stopped running — not because I read it was unsafe, just because I rather liked the idea of giving my body (and growing baby) a rest from pavement pounding,' she said.
Adding she was 'conscious of holding my tummy in (as if giving your baby a hug) to support my back and ensure that post-baby, my old favourite jeans will still fit... eventually.'