Wearing matching grey fleeces, the children from the 33rd Watoto Children’s Choir filed out of the pews of the Faith Community Church Sunday, smiling broadly as they approached the altar. Standing side by side in a few short lines, one behind the other, the 17 children — along with four of their adult leaders — were ready to sing. When they did, the smiles on the church members faces matched those of the children.

The leaders sang harmony, the children sang melody, all the while dancing with an energy that filled the room, adding color and spirit to an otherwise drab and rainy Sunday morning. The performance served as a brief preview of the choir’s free concert at the Tabernacle in Oak Bluffs on Thursday at 7 p.m.

The unfading ear-to-ear grins on the children’s angelic faces mask the personal traumas they have seen in their short lives. The choir is part of Watoto Child Care Ministries, which was founded as an outreach of Kampala Pentecostal Church in 1994 in response to the orphan crisis in Uganda. Currently the country is home to 1.8 million orphans who have lost their parents to the HIV/AIDS epidemic.

Watoto Child Care Ministries builds villages in Uganda where orphans live, go to school and learn trades. With the help of local leaders, Watoto’s social works department locates the most vulnerable children and houses them in the three villages. Usually the children are found living with their grandparents or other relatives in poverty, lacking food and clothing.

Choir leader Eddie Mwesigye — who got involved with Watoto Child Care Ministries through the Kampala Pentecostal Church five years ago — said the orphans’ lives are very difficult, with much of their time being devoted to finding something to eat, and many of them are abused by their relatives.

“Before they come to Watoto, all they think about is: ‘Am I going to get something to eat? I don’t have shoes. I can’t go to school. Will I ever grow up to amount to anything?’” said Mr. Mwesigye, seated at the front of the Faith Community Church after Sunday’s service.

Once located, Watoto Child Care Ministries pairs the orphans with widows or single mothers. Each mother lives in a house with her eight adopted children.

“Here they come into the village, they have a home with eight children. They have a mother who cares for them. They can go to school. They don’t have to worry about food. They don’t have to worry about where to sleep. They have their own beds,” said Mr. Mwesigye.

And once their basic needs are met, the children have the time and energy to start dreaming of better futures. Some aspire to be teachers, others doctors. “It’s just a total transformation,” Mr. Mwesigye said smiling warmly.

The Watoto Childcare Ministries provides everything from food and clothing to on-site schooling and medical care for the village residents. There are now 1,500 children divided among four Watoto villages. Mr. Mwesigye said the goal is to increase that number to 10,000.

“The need is great,” he pointed out.

Every year, different groups of children form choirs and travel to various places on the globe to raise awareness about the orphan problem in Uganda and the Watoto mission. The trips are financed through the sale of Watoto merchandise including CDs and clothing. Free-will donations given by audience members at the concerts go directly to fund existing villages and help build new ones.

Martha’s Vineyard is the first stop on choir number 33’s six-month tour of the northeastern U.S. The Watoto Children’s Choir number 33 has been hard at work for the past four to five months preparing for its first American concert.

“I like being in the Watoto choir because we raise awareness and support for the parentless children of our country, and I feel good if our country is better,” said 10-year-old choir member Maureen Bugonzi.

“As the choir travels, the children, through dance, through singing, tell their stories of how they have been helped,” said Mr. Mwesigye adding that none of the children had ever left Uganda before this trip.

Touring allows the children to grow physically and intellectually. “It’s something that also helps them to overcome the past,” Mr. Mwesigye added.

The children will be here through Thursday rehearsing their music and dances in preparation for Thursday’s concert. While they are here, they’ll be staying in dorms at The Fellowship of Christian Universities and Schools (FOCUS) whose 21-acre-campus in West Tisbury hosts conferences for middle and high school students in the summer.

The Watoto Children’s Choir’s Concert of Hope begins Thursday ay 7 p.m. at The Tabernacle in Oak Bluffs. Admission is free.