The Championship star is nearing a move after starring in the second tier last season, netting 15 times in 49 appearances.
Huddersfield Town were one of the favourites to sign the England Under 21 international, with the Terriers' odds of securing the 21-year-old's signature slashed to 8/1 earlier in the summer by SkyBet.
The Foxes were the only team at lower odds than Town to sign the youngster, and Claude Puel's side have made their move for the Canaries' playmaker.
Leicester have had a bid of around £20m for Maddison accepted by Norwich according to the BBC , with the former Coventry City man reportedly heading to the east midlands today for a medical.
Norwich's 2017/18 player of the season is thought to be the Foxes' replacement for Algerian winger Riyad Mahrez, who is being chased by Pep Guardiola's Manchester City this summer.