The Swiss star is taking part in the Match for Africa charity event this morning (3.30am) in his first match back since winning the Rotterdam Open.
Federer will partner Microsoft billionaire Bill Gates in a doubles match against Jack Sock and NBC Today show host Savannah Guthrie.
The 36-year-old will then have a three-set match with Sock, who is No 10 in the world rankings.
The aim of the annual event is to raise money for five different African charities along with the Roger Federer Foundation.
The game will take place in San Jose, California in front of 16,000 people but in preparation Federer has taken to Twitter to reveal what he eats in the build up to a game.
The world No 1 tweeted a picture of three bowls of pasta and a tray of baked vegetables.
He captioned the image with “Carbo loading before #MatchForAfrica.”
Federer will have to fill himself with carbohydrates to get through the four sets.
The 20-time Grand Slam champion has already raised questions over his body this year and claimed that he will have to miss out on some events as he reaches the latter part of his career.
But he still took part in the Australian Open and Rotterdam Open in the opening two months of 2018 – in which he won both.