Emma and co-host Marvin Humes joined the BBC show as presenters for the third series in 2014, but now that The Voice will be moving to rival channel ITV next year, the pair have no idea if they will be staying on the show.
The fifth series of The Voice, which will air on BBC from January, will be the last on that channel.
Speaking on Alan Carr's Chatty Man Christmas special, Emma - who is expecting her third child with husband Matt Willis - said: "We know nothing. We don't know if we've still got jobs. Anything can happen can't it?
"Shows go to new channels and people like to make changes so you just haven't got a clue. All we know right now is that we have done the absolute best job and series for the next one that we can and we are looking forward to the live shows, and who knows? Basically we haven't got a clue.
ITV confirmed last month that the BBC's singing show will change channel as part of a three-year deal, which will include a spin-off show on ITV2 and a two-series contract for The Voice Kids.
Before the broadcaster was revealed, BBC Acting Director Mark Linsey said in a statement that another broadcaster had "poached" the series. The Voice will air on ITV in 2017.
Alan Carr's Chatty Man Christmas special - 9pm, Channel 4, on Friday 25 December - Christmas Day
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