Caldwell has played a big part in Hibs' recent success

The 23-year-old Scotland defender has signed a pre-contract agreement and will move to Glasgow as a free agent.

News of talks between Strachan and Caldwell was made public last week after months of speculation.

And Caldwell was booed by a section of Hibs supporters during last weekend's defeat to Aberdeen at Easter Road.

Strachan completed the end-of-season signing of Wolves striker Kenny Miller on Tuesday as he continues to rebuild at Celtic Park.

Players are not doing anything wrong in this new free contract system, and people will have to get used to it. Gordon Strachan

Hibs lost previous skipper Ian Murray under similar circumstances - with the player moving to Rangers for nothing at the end of last season.

However, Hibs manager Tony Mowbray has vowed to keep selecting Caldwell and is confident the player will give his all for the remainder of his contract.

Caldwell was at fault for one of Aberdeen's goals on Saturday and Strachan joked: "I think Gary's back-pass could have a lot to do with the crowd's response.

"People will have to get used to this happening in this country.

"These players have been honest and are not kidding anybody else on.

"They have been open in saying they are going to Celtic - but they still want to do a job with their clubs.