According to TMZ, Rihanna, Charlie Sheen and Charlie Sheen's finance were all eating at the same restaurant in Santa Monica on Wednesday night (not together) when Charlie sent a request to Rihanna's table to have his fiancé meet her for her birthday.

Rihanna reportedly declined because 'there were too many paps' outside. 

Charlie got pretty upset and fired away on Twitter....

Among other things he posted...

Sorry we're not KOOL enough to warrant a blessing from the Princess. (or in this case the Village idiot)...and called her a #Hamateur

Rihanna went back at Charlie 

The same night, Charlie Sheen said he wanted to go back on 'Two and a Half Men' for an appearance in it's final season coming up