The Material Girl helped one fan with a proposal of a lifetime at her July 8 concert in Amsterdam.

In a YouTube video by user Edwin Smit, the singer, who is currently on her MDNA tour, is shown standing at the edge of the stage over the lucky couple.

"Who are you going to ask to marry you?" Madonna asked the woman. "Well, do you want to ask him to marry you in front of several hundred thousands of people?"

Madonna handed the mic over to the excited woman -- after warning her to not "slobber all over my microphone" -- who then asked her boyfriend to marry her. He said "yes," and a wave of cheers erupted from the crowd.

After taking her mic back, Madonna cheered the couple on, chanting, "Tongues! Tongues! Kiss with tongues!" as they kissed for all to see on the jumbotron.

"I'll give you once piece of advice. Never go to bed angry," Madonna told the couple before she got back to the music.

Madonna's advice is sound, but other celebrities aren't so sage when it comes to marital wisdom. Click through the slideshow to see stars whose advice on marriage shouldn't be taken.

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  • Khloe Kardashian

    Khloe Kardashian gave her big sis a few marriage pointers last year before Kim married Kris Humphries. On the talk show <a href="http://www.huffingtonpost.com/2011/08/19/khloe-kardashian-wedding-marriage-khloe-advice_n_931423.html" target="_hplink">"Naughty But Nice With Rob"</a>, Khloe said she keeps her marriage "hot" by being what she called a "slore:" a whore and a slut.

  • Katy Perry

    <a href="http://www.glamour.co.za/fashion-celebrity/more-hot-fashion/632837.html" target="_hplink"><em>Glamour </em> reported</a> that Katy Perry dropped in on a stranger's bachelorette party in London after her split from funny man Russell Brand in 2011. Perry offered the bride-to-be, Laura Cooney, some less-than-savory advice on her impending marriage: don't do it. Perry was later quoted as saying, "Let me tell you about permanence -- it doesn't exist."

  • Donald Trump

    Donald Trump recently offered some marriage advice to fellow money man Mark Zuckerberg. Before Zuckerberg's marriage to Priscilla Chan in May, Trump appeared on <a href="http://video.cnbc.com/gallery/?video=3000090374" target="_hplink">CNBC's "Squawk Box"</a>, saying the Facebook founder should sign a pre-nuptial agreement with his then-girlfriend. The Donald went on to say that Zuckerberg should only agree to give Chan $1 million in the event of a divorce.

  • Madonna

    The Material Girl just doesn't have marriage on her mind. After her divorce from Guy Ritchie, Madonna reportedly told fellow singer Britney Spears to "forget about marriage" because "it just doesn't work for girls like them," <a href="http://www.metro.co.uk/showbiz/405292-madonnas-marriage-advice-to-britney" target="_hplink"><em>Metro UK </em></a> reported. Madonna also said that she doesn't plan to marry again.

  • Jenna Dewan

    Channing Tatum and wife Jenna Dewan have made a strange vow... to not see each other very often. Dewan <a href="http://www.hollyscoop.com/channing-tatum/channing-tatum--jenna-dewan-reveal-their-baby-making-plans.html" target="_hplink"> told Hollyscoop</a> that their schedules make it hard to see each other more often than every two weeks. "We have a like a two week rule. So we see each other every two weeks," Dewan said.