Fellow Spaniard Fernando Alonso said he heard immediately after the second free practice session for the Japanese Grand Prix, as the news filtered around a shocked paddock at Suzuka.
De Villota, 33 and daughter of ex-Formula 1 driver Emilio de Villota, lost her right eye and suffered serious head injuries in a crash while testing for Marussia in July 2012.
Her body was found in a hotel room in Seville on Friday morning. Police said there were "no signs of violence" and that they were awaiting an autopsy.
"At the moment, I still can't believe it and need a while to stop and think about it. Of course, it's very sad news for the world of motorsport as Maria was loved by everyone.
"Now, all we can do is pray for her and for her family."
Marussia also expressed sadness at de Villota's death and posted a large picture of her on the home page of their website.
"Our thoughts and prayers are with Maria's family and friends at this very difficult time.
