Speaking to the media ahead of our pre-season match against Newcastle United on Sunday, Sonny said: "Before we start the press conference, I wanted to say I have decided to leave the Club this summer. Respectfully the club is helping me with this decision.
"It was the most difficult decision I have made in my career. Such amazing memories. It was so hard to make the decision.
"I need a new environment to push myself. I need a little bit of change - 10 years is a long time. I came to north London as a kid, 23 years old, such a young age. I leave this club as a grown man, a very proud man.
"I want to say thank you to all the Spurs fans for giving me so much love. I hope the goodbye is also good timing and this is the right time to make that decision. I hope everyone can accept that and respect that."
Asked for his reaction to the decision, Thomas said: "For me, personally, I would have loved to have worked with this fantastic person and player. He is a true Spurs legend in every aspect, one of the greatest players to play in the Premier League. It is never easy to find the perfect timing and me coming in from the side, it makes it a bit easier to end on a high."
One of our all-time greats, Sonny joined us at the end of August, 2015 and celebrated his 10th year at the Club by lifting the UEFA Europa League trophy back in May.
Fifth in our all-time goalscoring list with 173, last season Sonny became only the seventh player in our history to make 450+ appearances, reaching 454.
FIFA Puskas Award winner for his goal against Burnley in 2019, Premier League Golden Boot winner in 2021/22 with 23, firing us back into the UEFA Champions League, he is now one of just 13 players to lift a trophy as captain of Spurs.
We take on Newcastle at Seoul's World Cup Stadium on Sunday, kicking-off at 12noon, UK - live on SPURSPLAY.