Display an alert in a TableViewCell

I want to show an alert when I press a button that is in a tableviewcell and it gives me the following error:

  

'NSInvalidArgumentException', reason: 'Application tried to present modal view controller on itself. Presenting controller is.

This is my code:

 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "CeldaID", for: indexPath) as! ComprarTableViewCell

    cell.nombreEntradaLBL.text = nombreConcierto[indexPath.row]
    cell.comprarEntradaIMG.image = UIImage(named: imagenes[indexPath.row])
    cell.fechaEntradasLBL.text = fechas[indexPath.row]
    cell.comprarBTN.addTarget(self, action: #selector(ComprarTableViewController.mostrarAlerta), for: .touchUpInside)

    return cell
}

@objc func mostrarAlerta(){
    let alerta = UIAlertController(title: "Compra satisfactoria", message: "Se han comprado su entrada/as", preferredStyle: .alert)
    alerta.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
    alerta.present(alerta,animated: true)
}