Fries, shakes and a serenaded marriage proposal were on the menu May 21 at Spike Mendelson’s Good Stuff Eatery.

When Jonathan Murphy took his unsuspecting girlfriend Ashley Bowen to the burger joint, he’d planned the setting so that singers from D.C.’s a cappella group The Capital Hearings were there playing the parts of customers, employees and hungry bystanders.(They were, in fact, a bunch of tenors and altos.)

And, in true flash mob fashion, the proposal in its entirety was caught on tape.

Flash mobs are a continuing, organized trend in the D.C. area. For instance, if this ”Mamma Mia”-themed flash mob in Dupont Circle last May looks downright professional, that’s because it is — the DC Cowboys dance company organizes such performances periodically:

In April, a group of single ladies clad in heels took to the streets of D.C. to honor Beyonce’s hit of the same name:

Murphy’s musical choice was decidedly more indie — he proposed during a rendition of Built to Spill’s “Distopian Dream Girl” — but kudos to the groom-to-be — no matter how they’re organized, these things are hard to pull off.