They’re baa-ck.

The Basilica of St. Patrick’s Old Cathedral in NoLIta welcomed this year’s flock of sheep to its hallowed grounds this week. The ewes — named Houston, Prince and Spring — will spend six weeks “lambscaping” the lawn, helping to maintain the centuries-old courtyard while delighting onlookers.

“It’s one of the most anticipated happenings in the neighborhood,” said church administrator Frank Alfieri. “People line up six to seven deep on the sidewalk to see them.”

The parish began inviting sheep to graze in its courtyard for a few weeks during the summer of 2014, when the church’s long-time lawn-mower announced his retirement.

“I told him, ‘What do you expect us to do? Get sheep?’ ” pastor Monsignor Donald Sakano told The Post.

“And then I thought, ‘Wait, that’s an interesting idea!’ ”

The latest trio comes from Buckwheat Bridge, a wind- and solar-powered farm in Elizaville, NY, that raises sheep and goats for fiber production.

While this is Buckwheat’s second year collaborating with the Old St. Patrick’s, it’s the first trip to the big city for Houston, Prince and Spring. The 5-month-old ewes — named for three famous streets in their new neighborhood — put up little fuss during the hour-long ride from the Hudson Valley to Manhattan, but were eager to get on the lawn and begin munching on grass.

Spring, a sprightly black sheep, excitedly leapt from the van and jumped over an animal-wrangler to join her friends and start dining.

“They’re wonderful,” said Monsignor Sakano when he laid his eyes on the parish’s new residents. “They’re just the right size. Though they’re probably wondering when [we] are going to go away so they can chomp on the grass we’re standing on.”

They better get used to the attention: The wooly creatures will not only get a blessing from Sakano, but also a staff of five or six catering to their every need, including self-proclaimed “Shepherd of NoLiTa” Andrew Shermin, a 37-year-old parishioner and filmmaker who is the animals’ biggest fan.

“They’re stars,” he said of the trio. “It’s a really fun thing for the neighborhood. There’s nothing else like it in the city.”