ANGELINA JOLIE is one person who’s not happy about George Clooney’s engagement because she’s no fan of his fiancée and miffed that the two could knock her and Brad Pitt off their perch as America’s top celebrity humanitarians, say sources.

The 38-year-old Oscar winner and United Nations refugee goodwill ambassador took an instant dislike to Clooney’s high-powered bride-to-be, Amal Alamuddin, the sources add.

“Angelina’s fed up with all the fuss being made over Amal,” an insider told The ENQUIRER. “She’s tired of pals urging her to befriend Amal because of her impressive work as a humanitarian lawyer.”

Clooney’s stunning 36-year-old fiancee, a graduate of both Oxford and New York University Law School, is a United Nations commissions adviser who specializes in international law and human rights. She has worked closely with former UN Secretary General Kofi Annan and represented such headline-making figures as WikiLeaks founder Julian Assange.

“Angelina’s worked hard to establish herself as THE celebrity humanitarian, but now that George has Amal on his arm, she feels threatened that she and Brad, who also does charity work, can be knocked off their pedestal,” said the insider.

“Of course, Angie would never admit that, so instead she’s telling everyone that George is moving too fast with Amal.”

Although George, 53, recently stepped down from his United Nations “Messenger of Peace” role after six years, the source says he hasn’t given up on doing humanitarian work.

“George has no plans to stop crusading for human rights, and he considers Amal to be the perfect complement to his ambition in that arena,” explained the source. “But Angie envisions Amal and George stomping on her philanthropic ground, and she doesn’t like it one bit!”