Charlie's facial expressions are worth the price of admission..........

Yes we speculated on what he meant...it's not the first time he works alone with Mick though, stuff like Sad, Sad, Sad or Hold on to your Hat from SW was said (by M.Elliott I think) to be Jagger/Watts collaborations. Based on interviews from VL, a lot of the "groove" tracks that Was and Keith nixed were Jagger/Watts tracks too.

I remember that Keith said that when he got together with Mick in France in 2004 to write/record ABB they had just found out that Charlie was ill and that they were thinking "it's just the two of us now"...ironically with Keith's creativity  and interest in new music being close to nil since 1997, it now looks like it's come down to Mick and Charlie to get something going.