By Ben Simmons

Following on from his extraordinary 140-mile swim of the Thames, David Walliams is helping BT to raise £1 million for Sport Relief 2012 by joining a host of other stars to give you the time of day as the new voice of the BT Speaking Clock.

For five weeks only, one of the nation’s most recognised comic voices will join Chris Moyles, Kimberley Walsh, Gary Barlow and Fearne Cotton as the voice of the BT Speaking Clock. Between Wednesday March 7 and Monday April 9, BT will donate 10p for every call made to the BT Speaking Clock from a BT landline*, as part of its pledge to raise a whopping £1million for Sport Relief 2012.

To celebrate the new star voice, BT is running a competition on its Facebook page giving fans a chance to win a limited edition David Walliams wall clock. All you have to do is dial 123 from a BT landline between Wednesday March 7 and Monday April 9 for the BT Speaking Clock, raising vital funds for Sport Relief at the same time and guess the mystery celebrity voice telling the time that day. If you are right your name will automatically be placed in a daily prize draw to win.

David Walliams, said: “I was relieved to hear that BT only wanted my voice this time around and not for me to take on another gruelling challenge. I am thrilled to be the newest voice of the BT Speaking Clock, because it gives me another opportunity to help BT raise £1 million for Sport Relief, a worthy cause close to my heart. For the duration of the competition, every time you call to hear my dulcet tones from a BT landline, BT will donate 10p to Sport Relief 2012 — it’s as easy as 123.”

The BT Speaking clock has been providing the exact time since July 24, 1936 and is accurate to five thousandths of a second. The regular voice of the speaking clock is Sara Mendes da Costa, who became the fourth permanent voice of the BT Speaking Clock after winning a nationwide competition in 2007.

To call the BT Speaking Clock and hear David Walliams and all the other stars whilst raising money for Sport Relief at the same time, just dial 123 from any BT landline phone from today until April 9.