db={"docs":[{"_id":"7429437848adssk","title":"abc","actors":[{"name":"Mr.x"},{"name":"Mrs.Y"}]},{"_id":"7429437848adssg","title":"efg","actors":[{"name":"Mr.x"},{"name":"Mrs.z"}]},{"_id":"7429437848adssh","title":"hik","actors":[{"name":"Mrs.z"},{"name":"Mrs.Y"}]}],"actors":[{"name":"Mr.x","age":40},{"name":"Mrs.Y",age:25},{"name":"Mrs.z",age:87}]}

db.docs.aggregate([{$unwind:"$actors"},{$lookup:{from:"actors",localField:"actors.name",foreignField:"name",as:"actors"}},{$group:{_id:"$_id",title:{"$first":"$title"},actors:{$addToSet:{$arrayElemAt:["$actors",0]}}}},{$facet:{totalRecords:[{$count:"totalRecords"}],docs:[{$match:{}}]}},{$unwind:"$docs"},{$addFields:{totalRecords:{$arrayElemAt:["$totalRecords.totalRecords",0]}}}])