JKR wrote a scene for HBP, the movie?

[potioncat]

Now that I'm not checking HPANA and Leaky-Cauldron regularly, my 
Potter news seem to always come from the Washington Post. Today's 
Style section (Dec 5) has an article about Harry Potter. You can find 
it at Washingtonpost.com by searching for Beedle the Bard, or better 
yet, try "Under Harry's spell" The address is too long to make a 
link, and I haven't yet followed Carol's instructions for creating 
tinyurls.

The article is about about a local HP event and HP fandom in general. 
Of particular interest to me were quotes by our own Heidi Tandy. 
Here's one, "Well,we know she [JKR] wrote a new scene for Half-Blood 
Prince." (The question had to do with whether JKR would continue to 
write HP stories.)

But my question is, JKR wrote a scene for HBP? Do we know anything 
about it? Has she ever done that before? 

I know, she wrote the toad chorus but doesn't want to admit it!

Potioncat, who really does want to know.