LONDON — Pippa Middleton is following in her sister's footsteps — she's about to be a mother.

The younger sister of Kate, the Duchess of Cambridge, revealed in the publication Waitrose the "happy news" of her pregnancy and says she has passed her first trimester.

She is photographed working out and discusses how she has adapted her exercise routine to her condition. She promises to chronicle her pregnancy workouts for Waitrose, which is published by a British supermarket.

This will be the 34-year-old's first child. She married hedge fund manager James Matthews in 2017.

Her sister Kate had her third child — Prince Louis — earlier this spring,