Christina Aguilera used her pregnant tummy as a table top to write on a cup for her new hunger relief campaign with the WHR. Credit: Robb Dipple/Hilton Media Group

The bump has many uses! Christina Aguilera used her pregnant tummy as a prop in adorable new photos promoting the Tuesday, Aug. 5 launch of the World Hunger Relief's "Pass the Red Cup" challenge.

In the sweet snapshots, the pregnant star, 33, wears a denim jacket and white dress that cascades over her burgeoning bump. Aguilera, who's served as a global spokesperson for WHR (which benefits the U.N. World Food Programme) since 2009, uses her belly as a table top to write a message on a cup.

The star is challenging her fans to #PassTheRedCup on social media, which looks to fight global hunger.

In a blog post for Huffington Post, Aguilera explained why this cause in particular was so important. "It's heartbreaking to me that in our social media driven, increasingly-connected world, nearly 850 million people go to bed hungry each night," she wrote. "And this includes far too many children. It's a subject so close to my heart and has been for a long time, being a mom."

Aguilera reflected on her time in Rwanda, where she spent time at a refugee camp. "They told me how they escaped violence in the Democratic Republic of Congo," she recalled of the people. "Their courage and hope for a better life was incredible. On my trip, I served food to kids who walk miles to and from school each day to receive a hot meal. I also went to Haiti after the earthquake hit a few years ago and saw its devastating effects on many families. Kids there were so happy just to get rice and beans from WFP."

Like her first pregnancy, Aguilera has been eagerly baring her bump (and her body!). The Voice mentor recently stripped down for a new issue of V magazine, where she said: "As a woman, I'm proud to embrace my body through all stages of life, staying fearless and confident in surrendering to the unknowns the future has in store."

Us broke the news that the singer and fiance Matt Rutler were expecting their first kid together. Aguilera is already mom to 6-year-old Max, her son with ex-husband Jordan Bratman.