Serena Williams has admitted her “heart dropped” when she learned she was pregnant, initially thinking: “‘Oh my God, this can’t be...I had planned on winning Wimbledon this year”.

Williams, who is pregnant with her first child with her fiance Alexis Ohanian, said she had only taken a pregnancy test on the insistence of a friend, and did not truly believe the result until she had done six.

In an interview with Vanity Fair US, she said she had delivered the news to Ohanian after asking him to fly from San Francisco to Melbourne, where she was about to play the Australian Open, and handing him a bag with the tests in.