Tom Lees of Sheffield Wednesday
Lees was previously on a deal to last until 2019, and this deal takes him through to 2021.
The new contract was reward for two seasons of outstanding performances for the Owls, after leaving Leeds United in 2014 after struggling for form.
Tom Lees - Sheffield Wednesday
Leeds' decision to let him depart has been good for Sheffield Wednesday and positive for Lees' career, but it has not worked out well for the Whites, with their former defender now worth millions.
Premier League side Burnley attempted to buy him this summer, with The Mail reporting in late July that they rejected an offer of £5 million.
Lees was outstanding at the weekend as he shut out Aston Villa and new striker Ross McCormack, his former Leeds teammate, in a 1-0 win at Hillsborough.
Aston Villa's Ross McCormack in action with Sheffield Wednesday's Tom Lees
He will face his former side Leeds in a fortnight's time when the two teams clash in the Championship, as Carlos Carvalhal's look to mount another promotion challenge.
While Wednesday have moved forwards since Lees' arrival, his old side Leeds remain stuck in mid-table mediocrity and have not started this season well, with a 3-0 opening day loss to QPR.
Owls fans took great delight in revelling in Lees deciding to stay at the club, on social media by poking fun at Leeds after the announcement.
Swfc_Owls) August 8, 2016