The BT Speaking Clock has been taken over by some of the celebrities who scaled Mount Kilimanjaro for Comic Relief. But after the 12 March, Chris Moyles, Fearne Cotton, Cheryl Cole, Kimberley Walsh and Gary Barlow will be replaced by a mystery voice when you dial 123.
The mystery guest’s special appearance won’t be on for long – just three days.
However, BT will donate 10 pence per call to Comic Relief every time a call is made to the Speaking Clock from a BT landline between now and 23 March.
A BT spokeswoman said the funds raised by Comic Relief will help change the lives of children from across the UK and Africa.
"In Tanzania, malaria is the biggest killer of children and the money raised will go towards life saving equipment such as mosquito nets, as well as helping vulnerable, poor and disadvantaged people here in the UK," the spokeswoman said.
Visit BT’s website to find out more about how you can help BT raise money for Comic Relief visit.
Calls to the BT Speaking Clock cost 30p from BT Residential lines, while mobile and other providers’ costs may vary.