Egypt international Hegazi moved to The Hawthorns on a season-long loan deal from Al Ahly during the off-season, but the transfer garnered little attention with few people knowing much about the centre back's qualities.
Foster certainly did not know a great deal about his new team-mate, but he has been delighted with how quickly the 26-year-old has adapted to life in the Premier League.
"He's done amazing," Foster said, as reported by the Express and Star. "Nobody really knew too much about him when he came but from his first game he took to it so easy, he looked so comfy.
"To slot into the team in the Premier League as a big centre-back like he is, you think he might be limited with this and that, but he's got most of the attributes needed. He's just slotted in so quickly."
Hegazi has started all six of the Baggies Premier League matches to date this term, scoring on his competitive debut for the club against Bournemouth in August.