To mark World Aids Day on Monday, Breakfast welcomed a very special guest.
Gillian Anderson joined us live on Monday
We talked live to the American actress Gillian Anderson, who made her name as agent Scully in The X Files.
Gillian now lives in London - and she told us all about her campaigning work to highlight the problems caused by HIV and Aids, particularly in South Africa.
Across the world, more than 42 million people are now infected with HIV, the virus which leads to aids. It's predicted that number will more than double by the end of the decade.
Half of those suffering from HIV are women - and it's estimated that 14 million children around the world have been orphaned by the disease.
One of the cruellest aspects of Aids is that it strikes in the prime of life: half of those infected are aged under 24 or under.
That means the loss of farm-hands, factory workers, parents and teachers who would otherwise be at the peak of physical fitness.
For many HIV and Aids sufferers in the developed world, the impact of the disease has been lessened by modern combination therapy.
But there is little money for this in many developing countries.
Gillian Anderson will be talking to us about her work with the group Action for Southern Africa.
It estimates that 6,500 people die from Aids each day in Africa - and it's calling for the world's richest countries to set aside more money to tackle the problem of Aids and HIV across the world