Vincent Kompany says he is leaving Manchester City after 11 seasons.

The Belgium defender announced his decision on his social-media channels on Sunday, a day after captaining City in its FA Cup final win over Watford. That clinched a domestic treble, unprecedented in the men's game in England.

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Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Vincent Kompany says he is leaving Manchester City after 11 seasons.

Manchester City's Vincent Kompany, left, jumps for a header with Watford's Craig Cathcart during the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoKirsty Wigglesworth)

The 33-year-old Kompany didn't say what his next move would be.

Manchester City's Vincent Kompany, left, hugs Watford's Troy Deeney before the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany, left, hugs Watford's Troy Deeney before the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany lifts the trophy as celebrates with his teammates after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany lifts the trophy as celebrates with his teammates after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Kompany joined City in 2008, before the club came under Abu Dhabi ownership and became a major force in the English game.

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

The 33-year-old Kompany didn't say what his next move would be.

Manchester City's Vincent Kompany, left, jumps for a header with Watford's Craig Cathcart during the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoKirsty Wigglesworth)

Manchester City's Vincent Kompany, left, jumps for a header with Watford's Craig Cathcart during the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoKirsty Wigglesworth)

Manchester City's Vincent Kompany, left, hugs Watford's Troy Deeney before the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany, left, hugs Watford's Troy Deeney before the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany lifts the trophy as celebrates with his teammates after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's Vincent Kompany lifts the trophy as celebrates with his teammates after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)

Manchester City's team captain Vincent Kompany lifts the trophy after winning the English FA Cup Final soccer match between Manchester City and Watford at Wembley stadium in London, Saturday, May 18, 2019. Manchester City won 6-0. (AP PhotoTim Ireland)