Madonna also has two biological children, Lourdes and Rocco
Pop star Madonna has been urged by Save the Children to reconsider her apparent plans to adopt another Malawian child.
Malawian officials have indicated she will arrive in the African country this weekend in an attempt to adopt an orphan called Mercy James.
The UK-based charity said ideally orphans should be cared for by their extended family or community and taking them abroad was "not a solution".
Madonna took then 13-month-old David Banda to the UK from Malawi in 2006.
The Reuters news agency reported that it was told Mercy James has "no father and mother, they both died", and an assessment had been completed on Thursday.
Reuters reported that Mercy James was four years old, while the AFP agency said she was three.
Madonna is expected to arrive in Malawi to attend a procedural hearing at the country's High Court on Monday.
Save the Children spokesman Dominic Nutt told the BBC's Newshour programme: "For the most part so-called orphans in poor countries tend to have family still available to them, if not actually a parent still living.
"It is vital, we say, that children should not be taken abroad to be looked after but should be cared for in their own environment by their own community, ideally by their own family, particularly their extended family."
He said even if an orphaned child had no extended family, it was "much easier and better" to continue looking after them in their own country.
"The thing to do is to support the community, to support local agencies and charities who can look after the child so that the child is at least cared for in their community," he said.
"You cannot literally take every poor child who may only have one parent living, or no parent living, across the world and transport them all into Kensington in London. It's not a solution."
Madonna took David Banda to the UK from an orphanage three years ago and the official adoption of the boy was confirmed last year.
An official at the Malawian department of women and child welfare told the BBC's Raphael Tenthani that the pop star had already filed adoption papers and her case could be heard as early as next week.
The official later told the Reuters news agency: "We expect her over the weekend or earlier than that... but without a doubt she is coming before the end of this month."
Madonna's spokeswomen, Liz Rosenberg and Barbara Charone, and her lawyer in Malawi, Alan Chinula, have not commented.
However, a US government official - speaking under condition of anonymity - told Reuters that an adoption bid was under way.
Writing in response to e-mailed questions from Nation readers last week, Madonna said: "Many people - especially our Malawian friends - say that David should have a Malawian brother or sister.
"It's something I have been considering."
In 2006, critics accused the Malawian government of sidestepping laws banning foreign adoptions in order to allow the celebrity to take David home with her.
After the adoption was legalised, Madonna said the difficulties had arisen because "this adoption essentially was the beginning of the creation of adoption laws in Malawi".
She hoped it would make it easier for others to adopt from the country and explained: "I am the template or the role model, so to speak, for future adoptions."
The star also has two biological children - Rocco, her son with former husband Guy Ritchie, and Lourdes, whose father is Carlos Leon.
Film director Ritchie and Madonna's divorce was finalised in November.
Malawi does not, as a rule, approve adoptions for single or divorced people, but the official at the country's welfare department said that each case was considered on merit.