Premiership and SPL footballers will club together on Sunday to raise around £750,000 for a nurses hardship fund.
Henry is one of several high-profile players to back the campaign
Players like Thierry Henry and Steven Gerrard have donated a day's wage to the May Day for Nurses campaign, which is the idea of Dr Noreena Hertz.
"The money goes to a hardship fund and pretty much every nurse is eligible," Dr Hertz told Radio Five Live.
"This is for the thousands of nurses who've been writing to me who have to juggle two or three extra jobs."
In all, 239 players have pledged their earnings and whole clubs such as West Ham, Fulham and Tottenham Hotspur decided to back the cause.
Managers including Terry Venables, Sir Alex Ferguson, Sam Allardyce and Martin O'Neill and former players such as Jamie Redknapp and Graeme Le Saux are also taking part.
"It has not been easy," said Dr Hertz. "I really had no access and did not know anyone in football six months ago so it was just a matter of persistence.
"Every single Premiership club is now on board and almost half of the players are giving up their pay today. It has been a real success."
According to the campaign's manifesto, footballers are being asked to lead the way because of their high profile.
"The money donated by footballers will make a significant difference to the lives of several thousand people," the manifesto stated.
"Given how tough life as a nurse nowadays is, with inadequate pay, high stress, large student loans and no job security, having access to a hardship fund may make the difference between a nurse being able to continue and having to quit."
The money raised will go into a fund administered by the Royal College of Nursing and will be distributed to nurses for things like child care or transport to work.