Michael Schumacher's return to Formula One is expected to see ticket sales for the European Grand Prix rise by as much as 20 per cent, with millions more watching worldwide.

The seven-time world champion, who recorded an astonishing 91 wins as he dominated Formula One for the best part of a decade, will stand in for Ferrari 'for as long as it takes' for Felipe Massa to recover from the head injuries he sustained at the Hungarian Grand Prix.

"The most important thing first: thank God, all news concerning Felipe is positive, and I wish him all the best again," said Schumacher on his official website.

"This afternoon I met with team principal Stefano Domenicali and Ferrari president Luca di Montezemolo and together we decided that I will take the place of Felipe. Though it is true that the Formula One chapter has long been closed to me, it is also true that for loyalty reasons to the team I cannot ignore the unfortunate situation. But as the competitor I am, I also very much look forward to facing this challenge."

Schumacher will make his return at the European Grand Prix in Valencia. It is a major boost for organisers Valmor Sports, particularly as they had been facing the prospect of staging the race without home hero Fernando Alonso, whose Renault team have been suspended.

The German will undergo an intensive training programme in order to prepare for his comeback.