Why Do Presenters Hold Microphones To Singers When Wearing A Head Mic?

[LittleSquidge]

For instance, Lady Gaga X Factor 2013: she has a head microphone on and Dermot still holds a handheld baton mixrophone to her when interviewing.
Why use two?

[daffy654]

Her head mic will be switched off, it is set up to transmit singing to the audience, not talking to camera.

[gingejbee]

...because TV is all smoke and mirrors, as they say!

[andy-hughes]

Or, as is sometimes the case, even though the artist is wearing a head-mic, they may still be miming!

[ABerrant]

The head mic broadcasts to the auditorium not the TV control gallery and is probably turned off when not singing so that normal conversation is not broadcast.

[loobylou]

Anyone know what Louis (I think) said off camera when Luke kissed him and the boys? I've replayed several times and still can't make it out - he didn't sound pleased though.

[Blackiequine]

If you're still on the channel and have rewind facility, in real time put on subtitles then rewind to the spot, it might just be there. Mind you a lot of subtitles bear no resemblance to reality, I feel sorry for people who totally rely on them.