The 26-year-old Tielemans, who joined from Monaco on loan in 2019 before signing a permanent deal, holds a special place in Leicester's history after scoring the winning goal in the 2021 FA Cup final against Chelsea.
He is out of contract this summer and will not be staying around to help Leicester return to the top division after their relegation, which came seven years after the team won the Premier League.
"From the first day I set foot on this ground, your warmth and passion embraced me," Tielemans said in a video on Instagram. "Victory and triumph, love, hope and even defeat, we've shared many special moments together.
"This is not a goodbye," he added, "but a heartfelt farewell."