Actor Hugh Grant is backing a scheme to find missing children after fatherhood gave him a new insight into the hell parents face when a child vanishes.

The Notting Hill star is a patron of the Missing People charity and he is urging his fans to download a cell phone app which alerts the user when a youngster in the same area is reported as lost.

Grant is close friends with Brits Kate and Gerry MCCann, whose daughter Madeleine disappeared at the age of three during a family holiday in Portugal in 2007, and he admits the thought of having to go through the same agony haunts him.

The actor tells U.K. Tv show Good Morning Britain, "I've got to know the MCCanns in particular over the last few years and it was through that that I realised what a brilliant idea this is. We've got our smartphones doing relatively useless, vain things and to have them doing something unbelievably important... If one of my children went missing... I am told it's the first hour or two that's really crucial (in the search)."

Grant fathered three children in a 15-month period - he has a daughter Tabitha, three, and son Felix Chang, 22 months, by his ex-girlfriend Tinglan Hong, and a two-year-old son by Swedish Tv presenter Anna Eberstein.