The life-size digital likeness of Qian, complete with his trademark endearing smile, however, shared his view on metaverse, a three-dimensional digital space that uses advanced tech like virtual reality and augmented reality.

Qian Yonggang, son of Qian Xuesen, said in a note that the digital likeness of his father will be used only to inspire scientists to make more innovations in the country so as to benefit society.

In the case of digital Teng, technologies like facial capture, rendering, machine learning, high-resolution 3D modeling, animation processing and visual enhancement went into the recreation of the singer's likeness, said Hong Kong-listed Digital Domain Ltd Holdings, its producer.

Millions of online viewers reportedly dropped their jaws in utter disbelief at the likeness of Teng whose digital avatar came complete with her famed sweet smile and signature gestures.

And Digital Domain, "her" producer, said several technologies like facial capture, rendering, machine learning, high-resolution 3-D modeling, animation processing and visual enhancement went into recreation of the singer's likeness.