Grealish made the big move to the blue side of Manchester after more than seven years at Aston Villa to play under Pep Guardiola.
Manchester City's winger has been in a serious, long-term relationship with Sasha Attwood. Read everything about his girlfriend.
Brighton are winless in their last four matches and are placed eight in the standings with 15 points from ten games.
Manchester City have 23 points from 10 matches to sit second in the standings and are four points behind leaders Arsenal.
A win at the weekend will not necessarily move Nottingham out of the bottom three but it will be a good launching pad for success.
Liverpool are seventh in the table with 16 points from 10 games, while Nottingham only have six points from 11 matches.
Sitting third in the Premier League table, Tottenham Hotspur have 20 points from nine matches. They are three points behind second-placed Manchester City.
Grealish rose through the ranks of English football, joining Aston Villa as a youth player. He then signed a youth loan with Notts County.
Copenhagen will host Manchester City in a UEFA Champions League fixture at Parken on Tuesday.
In Group E, Omonia have lost both their matches to sit at the bottom spot, while United are second with three points from two games.