While Pitt calls his fiancee "Miffy", Jolie replies by calling him "Kitty" and other people's presence do not make them conscious about it, reported Sun online.
"Brad and Angelina are very lovey-dovey towards each other and don't care who sees it," a source said.
The couple raise six children together, Maddox, 11, Pax, 9, Zahara, 7, Shiloh, 6, and four-year-old twins Knox and Vivienne. They are planning to tie the knot soon.