Harry Redknapp says he will not be paid for his three-game stint in charge of Birmingham City if he fails to keep them in the Championship.
The 70-year-old agreed to take over at St Andrew's on Tuesday, a day after Gianfranco Zola resigned.
"I'm not being paid. It doesn't bother me though," Redknapp told BBC Radio 5 live.
"I have got a bonus. It's not a massive one, but I said 'if I don't keep you up, I don't want paying'."
Former West Ham, Tottenham and Portsmouth manager Redknapp revealed he had the same arrangement when he worked as an adviser to Derby County at the end of last season.
He added: "I said to them 'if you don't make the play-offs, I don't want any money'. If we hadn't made the play-offs, I wouldn't have got paid anything."
'I'm ready for it'
Redknapp has not managed in English football since leaving QPR in February 2015 but is confident he can have an energising effect on Blues, who are only three points clear of the relegation zone.
He said: "When a team only wins two out of 24, it tells you it's not going to be easy. But you've got to believe in yourself and believe in the team.
"I've been in these sort of situations before. They're always difficult, but I'm ready for it."
His first game in charge is away to local rivals Aston Villa on Sunday, and Blues then face Huddersfield at home before finishing the season away at Bristol City.
And although Redknapp is initially only involved for those three matches, and has attended just one training session so far, he has already seen enough in the club to believe it can challenge for the top six - if he can mastermind survival.
"I think if we can stay up this year, the potential is here to build a team that next year would be looking at the play-offs," he said.
"It's not that difficult to put together a good team in the Championship, if you know what you're doing. You can go out and pick up players, you haven't got to spend fortunes.
"Right now, it's tight at the bottom. Wigan and Blackburn have still got a big chance, so we're going to need some points from somewhere, starting if we can on Sunday."