Music Directors Singging in Other Music Director's Songs

[dinesh2002]

Discus it here...as i know

1.A.R.Rahman - MSV
2.Haris Jeyaraj - Ramesh Vinayagam
3.YSR - IR
4.KR - IR

can anyone complete my list.... as im quite blur about yesteryears composers in todays songs.... all im wondering :

When is this gonna happen :

1.ARR - IR,( a combo that everyone in tami sure will look foward)
YSR, HJ
2.Hj - ARR ( a combo that everyone in tami sure will look foward)
3.YSR - ARR