17-year-old boy charged with murder of Elianne Andam, 15

A 17-year-old boy was charged Friday with murdering Elianne Andam, the 15-year-old schoolgirl who was stabbed to death on a London bus — as British actor Idris Elba joined those expressing his heartache and horror.

The teenage suspect, who was not identified because of his age, appeared at youth court Friday charged with murder and possession of a knife, London’s Metropolitan Police said.

He was remanded in custody until Tuesday when he will appear at the UK’s top criminal court, the Old Bailey.

The suspect was busted just over an hour after Andam was stabbed to death on her way to school on Wednesday morning, the force said.

Late Thursday, more than 20 of the dead girl’s family members were taken by cops to the scene of the crime, according to The Times of London.

“We as a family are struggling to comprehend this painful tragedy that has happened to our beautiful daughter and beloved sister, Elianne,” the family said in a statement read by the Bishop of Croydon, Dr Rosemarie Mallett.

“Our hearts are broken and we are overwhelmed by sorrow and grief,” the family said of the girl who “was a beautiful person, inside and out.”

“She was intelligent, thoughtful, kind and had a bright future ahead of her,” they said of the young teen who wanted to be a lawyer.

The murder has horrified the UK, which has seen an alarming trend of knife crimes.

“Luther” star Elba, 51, highlighted the case Friday in a tweet saying: “We NEED to enforce tougher deterrents and punishments to carrying these weapons.”

“Sending my condolences to the family of Elianne Andam at this very sad time,” he wrote.

“It is a shame that our country still mourns the deaths of children at the hands of knives.”