By Natalie Jamieson
Newsbeat entertainment reporter
Leona Lewis has said that a recent trip to South Africa for Sport Relief has changed her outlook on life.
Leona Lewis recorded the Sport Relief song Footprints In The Sand
Newsbeat joined the singer on the three-day trip as she visited projects funded by the charity.
She said: "Sometimes you will see an advert on TV and you'll think about it for five minutes and then you kind of switch over and you switch off and don't think about it anymore. But these are not just faces, they're people."
The day after the Brit Awards you may have thought Leona Lewis would be sobbing into her cornflakes after coming home without any trophies, but no.
Leona said: "I think a lot of people were like, 'Oh she is so disappointed and upset'. Do you know what, I was coming to South Africa the day after and I was looking forward to that so much! I got to perform and that was the main thing for me."
Leona was approached to provide this year's Sport Relief single, Footprints in the Sand, and off the back of that, was given the chance to see how some of the charity money gets spent.
That is how she ended up on a flight to Johannesburg, (with her dad, boyfriend and publicist for company) visiting a variety of projects in and around the city.
The first day was taken up at the Leth'ithemba Care Centre for children affected by HIV/AIDS, about a half hour's drive outside Johannesburg.
Leona was welcomed with a traditional Zulu dance by the pre-schoolers.
She said: "Most of them are orphaned or have lost one or both parents. They were just so amazing and so happy and singing and dancing and so smiley and just want to give you hugs."
There is a health clinic attached where sick relatives get advice or home care treatment while the children are looked after at the centre.
Leona Lewis visited a day care centre for children with HIV/AIDS
Some of them are healthy but many are sick, so as well as reciting things like Twinkle Twinkle Little Star, they are taught rhymes about child abuse and warning not to touch another child if he or she accidentally gets a cut while playing.
Leona accompanies two of the under-fives to see where they live.
It is a three-room brick house with no bathroom.
Their grandmother is the sole provider following the death of her sister, the children's mother.
She also has two children of her own to take care of.
The grandmother breaks down when she explains that there is no money and often no food.
Leona follows suit. She said: "She's having to provide on her own and it just makes me feel that we all have to really do something."
Leona then goes to be comforted by her own family.
She added: "It is so hard to see people living in these conditions and I came back to the hotel and there's literally food in abundance."
Back on the radio
Day two involves a trip to a township called Tembisa, home to about a million people.
Leona Lewis spent a morning being grilled by two nine-year-olds
At a community radio station, Leona gets quizzed by a pair of nine-year-old breakfast show hosts.
They do not know who Leona is but have done their research and ask about winning the X Factor and being signed by Atlantic Records mogul Clive Davis in America.
There is one sticky moment when a question gets misread and Leona is asked if she is still a virgin.
Live on air there is an embarrassing pause, before the proper question is revealed as, 'are you still a vegetarian'.
"The little boy got his words mixed up, it was quite funny," Leona said laughing afterwards. "He was really sweet. He was like, 'What? What's so funny?' He didn't understand."
Next stop is a place called Safe Park, an after school centre where children and teenagers come to hang out, learn, sing and get counselling if needed.
While the boys are playing football or cricket, the girls are drawing or singing Beyonce and Mary J Blige songs.
Some of the older children do know who Leona is here and have heard Bleeding Love played on the radio.
Living in a slum
The last stop on day two is to a slum on an old industrial estate of Johannesburg.
About 900 people are living on an old gold mine in a variety of shacks, made out of anything they can get their hands on; cardboard, plywood, sheets of metal.
This is the view from the children's day care centre in South Africa
The nearest clean water is a two-mile walk away.
The elders of the community take Leona on a tour but it is not long before the intrusion of the cameras and strangers creates an unsettling atmosphere.
Some of them have been drinking and start to demand attention. Leona's publicist pulls her out.
Back at the hotel Leona says those conditions were not even fit for an animal to live in, let alone people.
She said: "It was dire, the situation was devastating."
The last day
The final excursion on day three is an hour-long drive to Pretoria to see a teenage girl's soccer team in action.
It was set up for those who have been affected by domestic violence, by an organisation that runs a women's shelter.
Volunteers at the health care clinic for sick parents and relatives
Leona can not believe the trip has come to an end.
She said: "This has been life-changing for me, it's kind of like an epiphany. I'm taking this with me forever and I hope to come back and do many more trips."
And she is not fussed about becoming one of those celebrities, like Chris Martin or Bono, renowned for talking charity.
She said: "It's an issue and it's all relevant because this is going on. I think they're just trying to keep people remembering.
"It's not all about sadness and upset, it's about hope and doing something to help and make it better for people."