Fresh off the announcement of Brad Pitt and Angelina Jolie's engagement, we've all got engagement rings on the brain. A common rule suggests the bling that's purchased to propose with should be worth two months' salary, but we can't help but wonder how that applies to the hotties in Hollywood who can rake in millions in a month.

Watch the video above to find out how much these stars dropped on engagement rings.

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And of course, check out the most expensive celeb weddings that didn't last:
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  • Kim Kardashian & Kris Humphries: $6 million

    In August 2011, Kim Kardashian and Kris Humphries were married in an estimated <a href="http://www.hollywoodreporter.com/news/kim-kardashians-wedding-cost-by-the-numbers-227691" target="_hplink">$6 million wedding</a>, though Kardashian's wedding planner has said that the <a href="http://www.hollywoodreporter.com/news/kim-kardashians-wedding-cost-by-the-numbers-227691" target="_hplink">reality star received discounts</a> from vendors. The couple separated in October after 72 days of marriage.

  • Liza Minnelli & David Gest: $3.5 million

    Liza Minnelli and David Gest reportedly spent <a href="http://www.usatoday.com/life/people/story/2011-11-01/cost-of-celebrity-weddings/51019708/1" target="_hplink">$3.5 million</a> on their March 2002 wedding, which featured a twelve-layer wedding cake and performance by Tony Bennett. The couple divorced in July 2003 after a year of marriage.

  • Elizabeth Taylor & Larry Fortensky: $2 million

    Elizabeth Taylor and Larry Fortensky were married in a <a href="http://www.people.com/people/archive/article/0,,20111095,00.html" target="_hplink">$2 million</a> celebration in 1991, though <a href="http://www.ivillage.com/elizabeth-taylors-ex-husband-larry-fortensky-gives-last-interview/1-a-343349" target="_hplink">they split in 1996</a> after five years of marriage.

  • Paul McCartney & Heather Mills: $3 million

    Paul McCartney and Heather Mills' June 2002 wedding cost an estimated <a href="http://www.forbes.com/2007/07/12/celebrity-media-weddings-biz-media-cz_lg_ts_0712celebweddings_slide_20.html?thisSpeed=30000" target="_hplink">$3 million</a>. They split in May 2006.

  • Elizabeth Hurley & Arun Nayar: $2.5 million

    Elizabeth Hurley and Arun Nayar reportedly spent <a href="http://www.elistmania.com/juice/10_most_expensive_weddings/ http://www.people.com/people/archive/article/0,,20061684,00.html" target="_hplink">$2.5 million</a> on their week-long wedding in 2007. Hurley filed for divorce in 2011 after four years of marriage.