"Most comfortable look from today's shoot! #wearitpink @bccampaign," she wrote on Instagram alongside a snap of herself in the pig outfit.
The style blogger was supporting Breast Cancer Campaign's #wearitpink for breast cancer awareness month.
Earlier this month Millie glammed up and donned an air hostess uniform at airline Virgin Atlantic's exclusive lounge.
Sporting the company's trademark red and tipping a captain's hat, Millie looked quite the part as she posed with the Virgin crew. Completing her look was Virgin Red lipstick and a high chignon.
Millie recently came back from her honeymoon and immediately was forced to deny pregnancy rumours that were circulating.
"Pregnancy rumours are just that.. We are far too busy enjoying each other right now", she said.
The denial came a day after she and Professor Green made their first official appearance as married couple.