Myleene Klass and Gethin Jones are hosting a mass protest rally today to demand the G8 act on the issue of world hunger.
The event will include appearances from a number of campaign supporters including Grammy Award winning singer Angelique Kidjo, and specially recorded messages from David Beckham.
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The memorial service will be attended by Prince Harry and Meghan Markle.
David Browning admits manslaughter by diminished responsibility but denies murder.
Four people have died and the suspect is still at large, police said.