IN THIS ISSUE: Angelina's Birthday Ends in Tears

Angelina Jolie's 35th birthday was supposed to be a day of family fun, but instead it ended in a screaming match with Brad Pitt.

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The trouble between the couple began on June 3, the day before her birthday, when Brad took off from their Los Feliz estate by himself.

Witnesses say the actor, 46, appeared lost in thought as he spent hours drinking beer in the back of a chauffeur-driven SUV, riding aimlessly around L.A.

"I don't think Angelina knew where he went and that is probably why she got so mad," says the source. "There was some speculation that he was hoping to see Jennifer Aniston."

When Brad returned home, a fierce argument erupted.

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Angelina, says a source, burst into tears and canceled the family's plans to go see Sesame Street Live at the Nokia Theater in Los Angeles on her June 4 birthday.

"All the kids were looking forward to it," says the source.

"Afterward, Brad and Angelina had expected to do something romantic."

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But after their argument, Angie was too furious to celebrate. "At the last minute she told the staff the whole thing was off," says the source.

"She didn't give any reason, just said that they weren't needed and that she and Brad and the kids were going to stay home."

FOR MORE ON HOW ANGELINA'S BIRTHDAY ENDED IN TEARS — AND WHY SHE FEELS THREATENED — CHECK OUT THE NEW ISSUE OF OK! IN STORE NOW!