Simon Cowell has revealed L.A. Reid is already regretting quitting 'The X Factor' USA.

The songwriter announced last week he would leave the show's judging panel at the end of the second series to concentrate on his job as chairman of Epic Records, but head judge Simon doesn't think L.A. has come to terms with his departure.

Speaking to E! News, Simon said L.A. was ''regretting his decision, trust me''.

However, the 56-year-old record producer - who is joined on the panel by Simon, Britney Spears and Demi Lovato - knew he would only make a short-term commitment to the series, but will continue to work with the 'X Factor' boss on other projects.

He explained: ''I came into this knowing that it wasn't gonna become my life.

''Simon and I are really good friends, and he knew at some point I needed to get back to work.''

Reflecting on his time on 'The X Factor' USA - which concludes its second series tonight (20.12.12) - L.A. admitted he would really miss finding talented contestants.

L.A. said: ''Watching people come in an unknown and walking away famous, and some of them walking away real stars - that's the greatest feeling in the world.''

Although a judge's seat is now empty, Simon isn't in a hurry to find a new panellist for the show, which has been renewed for a third series in 2013.

He said: ''It'd be crazy to think about it while the show's still on. I'll take a couple weeks off [after Thursday's finale], regroup, and wait for the calls to come in. I prefer that.''