The German motor racing legend, who retired in 2006, will replace injured Felipe Massa in the European Grand Prix in Valencia on August 23, and possibly for the remainder of the season.
"The Ferrari-Marlboro team plans to give Michael Schumacher Felipe Massa's car until the Brazilian returns to competition," Ferrari announced in a statement on its website carried by Italian news agency ANSA.
The statement added: "Michael Schumacher says he is available and in the coming days he will pursue a specific programme of preparation at the end of which it will be possible to confirm his participation in the European Grand Prix."
Schumacher, 40, commented: "Ultimately I like challenges and this is a great challenge."
"The important thing is that Massa gets better," he continued, adding that he "just wanted to help the firm (Ferrari) when they needed it".
Schumacher, who last test drove for Ferrari in April last year, was pleased, though, that the most recent update on the unlucky Brazilian was encouraging.
"The most important thing, first thank God, all news concerning Felipe (Massa) is positive," he was quoted as saying on the official Formula One website.
"I wish him all the best again. I was meeting this afternoon with (Ferrari team chief) Stefano Domenicali and (Ferrari president) Luca di Montezemolo and together we decided that I will prepare myself to take the place of Felipe.
"Though it is true that the Formula One chapter has been completely closed for me for a long time, it is also true that for reasons of loyalty to the team I cannot ignore this unfortunate situation," he said. "But as a competitor I also very much look forward to facing this."
News of his comeback to the sport he virtually made his own came 24 hours after the possibility had first been raised by his spokeswoman, Sabine Kehm.
"The whole thing will be considered by Ferrari. If they approach Michael, then he will consider it," Kehm had told BBC Sport.
She added: "Usually, I would say he's not interested because he's fine with his life and he doesn't miss anything but now the situation is so different - it's very hypothetical - and Michael doesn't want to step into that (discussion)."
Schumacher, who is on Ferrari's pay roll as an advisor, will be filling in for Massa, who is recovering from surgery following his horrific high speed crash in qualifying for last weekend's Hungarian Grand Prix.
Only this month he had made it clear speaking at the German Grand Prix that he was not interested in making a full time comeback.
But the offer of a temporary return to the Ferrari cockpit obviosuly proved too much to resist for 'Schumi' who has recovered from a neck injury sustained in a motorcycle accident in February.