Fernando Alonso's milestone 400th Grand Prix weekend has started on a less than ideal note.

The 43-year-old Spaniard, who participated in a sponsor event for Hugo Boss in Mexico City on Wednesday, was absent from the circuit on Thursday due to illness.

"Fernando Alonso is feeling unwell and will therefore not attend media day," confirmed his team, Aston Martin. "Fernando is focused on feeling 100 percent for Friday and his planned return to the car for FP2."

Alonso was always scheduled to sit out the first Friday session in favor of Aston Martin's rookie reserve driver, Felipe Drugovich. The 24-year-old Brazilian also took Alonso's place in Thursday's official FIA press conference.

"I think the only thing that wasn't planned for me is actually the press conference," Drugovich smiled. "So, yeah, my best wishes to Fernando. Let's see how he gets on tomorrow." body check tags ::