Need HELP finding song that Beyonce samples...

Okay, so in Beyonce's documentary 'Life Is But A Dream' there is a performance of Single Ladies. The intro/monologue to the performance samples what sounds like an old disco song maybe from the 70's or 80's. The sample sounds really familiar and it seems impossible to Google since I only know the part that is used as an actual sample and none of the actual lyrics. Below is a link to the moment the sample starts in the performance.

http://youtu.be/z6udaPKnLV0?t=1h27m18s (The sample is at the 1h27m18s mark)

The sample is repeated maybe once or twice in her monologue. The "do do do do do do do..." part is the sample I want to know the name of! Thank you!

That's Jay-Z - The Dynasty Intro sampling Kleeer - She Said She Loves Me