What is the cosmological effect of singer Zayn Malik leaving the best-selling boy band One Direction and consequently disappointing millions of teenage girls around the world?

The advice of British cosmologist Stephen Hawking to heartbroken fans is to follow theoretical physics, because Malik may well still be a member of the pop group in another universe.

Stephen Hawking

'It would not be beyond the realms of possibility that somewhere outside of our own universe lies another, different universe and, in that universe, Zayn is still in One Direction,' physicist Stephen Hawking says. (Ted S. Warren/Associated Press)

The physicist took a break from speaking about his work as one of the world's leading scientists to answer the question from one upset fan during a talk at Sydney Opera House on the weekend.

"Finally a question about something important," Hawking, who appeared via hologram, said to loud laughs from the audience.

"My advice to any heartbroken young girl is to pay attention to the study of theoretical physics because, one day, there may well be proof of multiple universes.

"It would not be beyond the realms of possibility that somewhere outside of our own universe lies another, different universe and, in that universe, Zayn is still in One Direction."

Appeared as a hologram

The wheelchair-bound scientist, who was diagnosed with motor neuron disease at the age of 21, appeared at the talk in the form of a hologram streamed from Cambridge, England.

Now 73, he is known for his work on black holes and his international bestseller A Brief History of Time.

Malik quit the band last month, saying he wanted to live a normal life after five years of touring and performing.