Apparently Robbie was asked to record champions, and he in turned asked Queen to join him.

Brian stated that they (Roger and himself) found it stimulating to work with Robbie, and if it continues to be so, they will work together in the future as well.

On another front Roger in his question and answer session said that, while there are no definate plans, that sometime in the next ten year he would like to tour with Queen.

Source: Fan Club convetion - check out the fan clubs web site at http://www.queenworld.com/