Scotsman Paul Di Resta is to race alongside Lance Stroll this weekend after Felipe Massa withdrew due to feeling sick and dizzy.
The Brazilian complained of feeling sick and dizzy on Friday and was taken to the tracks medical centre for checks.
He was then transferred to a hospital in Budapest but no serious issues were reported. He was therefore given the all clear to drive on Saturday morning.
However, he suffered a relapse during FP3 and thus has decided to withdraw himself from the weekend.
Therefore Williams reserve driver and Sky Sports F1 commentator Paul Di Resta was called up.
He last drove in F1 before retiring at the 2013 Brazilian GP for Force India.
A statement from Williams said:
“After feeling unwell during practice in Budapest on Friday and Saturday, Felipe Massa will not drive for the remainder of the Hungarian Grand Prix weekend.
“Felipe visited the medical centre and the MH EK Honvedkorhaz hospital for precautionary tests on Friday, after feeling unwell and dizzy during FP2. He was cleared to take part in Saturday’s practice session by the FIA medical delegate, but he felt unwell again during FP3 and has made the decision to withdraw from the weekend.
“Williams supports Felipe’s decision and the team will work with him to ensure he makes a full recovery, with a view to return to the race track for the Belgian Grand Prix.
“Following this decision, the team’s reserve driver Paul Di Resta will drive alongside Lance Stroll for the remainder of the Hungarian Grand Prix weekend.”