The contest will be Hewitt's first competitive outing in three months following foot surgery in March.
Hewitt snapped a 15-match losing streak against Federer in last year's final of the grass court tournament at Halle.
Judging by the Swiss superstar's victory in Friday's semi-final win over Novak Djokovic at the French Open, Hewitt could be in for a torrid return to action.
Six-time Wimbledon champion Federer's showings in Paris suggested he is going to be incredibly tough work on grass for any player this year, let alone one on the comeback trail.
If world number 67 Hewitt loses in the opening round, he may slip out of the world's top 100 and leave Australia without a men's singles player with a double digit ranking.
Hewitt, who was a late withdrawal from Roland Garros last month, must consider himself highly unlucky to have drawn Federer first-up in the 32-man draw.
The Australian is trying to cram in as many matches as possible before the third grand slam of the year and will play in Eastbourne, England, in the week before Wimbledon.
- AAPTags: sport, tennis, germany