Gwyneth Paltrow wasn't exactly celebrating when her ex, Brad Pitt, tied the knot with Jennifer Aniston back in 2000.

According to a new unauthorized biography hitting shelves on July 29.

In the upcoming book "Gwyneth: The Biography," author Amy Odell reveals that Gwyneth Paltrow confided in friends about feeling "sad" after hearing the news that Brad Pitt had married "Friends" star Jennifer Aniston.

While publicly she kept her feelings under wraps, the book claims Paltrow shared harsh opinions behind the scenes.

"At one dinner, the two were talking about Brad Pitt," Odell writes, referencing a conversation between Paltrow and cosmetics heiress Aerin Lauder, TMZ said. "According to someone familiar with the discussion, Gwyneth allegedly told her, 'He's dumber than a sack of s---.'"

The book says Paltrow, now 52, became known among friends for mocking Pitt's "terrible taste in women," and that she had trouble hiding her emotions during a 2000 interview at the Toronto Film Festival.

When asked how she felt about the marriage, she allegedly gave the reporter a sharp look and said, "Are you really asking me this question? I can't comment on this kind of thing."

Paltrow Had Doubts About Pitt, Admitted Crush on Hugh Grant

According to PageSix, Gwyneth Paltrow and Brad Pitt began dating in the mid-1990s after crossing paths on the set of the thriller "Se7en," and their relationship lasted until 1997.

The pair got engaged in 1996 but called off the engagement a year later, without ever giving a clear reason for the split.

Around the same time, Paltrow reportedly told crew members on the set of "Emma" that she had doubts about Pitt and even confessed to having a crush on actor Hugh Grant.

Gwyneth Paltrow once reflected on the differences in her and Brad Pitt's backgrounds, mentioning that during their time together, she even found herself explaining things like types of caviar to him while on dates.

After ending things with Gwyneth Paltrow, Brad Pitt moved on and started seeing Jennifer Aniston in 1998.

Their romance quickly progressed—he popped the question the next year, and they tied the knot in Malibu in July 2000.

The marriage eventually ended in 2005, shortly after Pitt grew close to his "Mr. & Mrs. Smith" co-star, Angelina Jolie.

Paltrow moved on to actor Ben Affleck and later married Coldplay frontman Chris Martin, with whom she shares two children. That marriage ended in 2014. She is now married to TV producer Brad Falchuk.

Tags
Gwyneth Paltrow, Jennifer Aniston, Brad Pitt