Trevor Sinclair, who played with the 34-year-old at Manchester City, is backing his former team-mate to make an international comeback
The 34-year-old joined the Hoops at the start of the season, helping to fill a position that had proved problematic for the Parkhead club last year as Greek flop Vasilis Barkas and Scott Bain shared the gloves.
The former Manchester City and Tottenham shot-stopper has reignited his career in Glasgow’s East End with a number of standout displays between the sticks.
His impressive string of performance’s havent gone unnoticed, leading Sinclair to admit an international comeback isn’t beyond his former team-mate.
Hart earned the last of his 75 England caps in a friendly against Brazil in November 2017.
Sinclair, who represented the Three Lions during the 2002 World Cup finals in Japan, added: “Joe has put himself right up there with the top keepers in Scotland.
“He’s got the experience — and, you never know, that England door might not be completely closed.
“Stranger things have happened, particularly if he is playing Champions League next year. Let’s hope so.
“The move (to Celtic) was the perfect fit. I’m so pleased for Joe and I’ve said that to him.
“Both Celtic and Manchester City are huge clubs. I played with him when he was young at City, saw him progress to become England No. 1.
“Now I’ve watched him play for my club, Celtic, and I’m really proud of his achievements.
“When you’ve had a dip in form, people criticise you and ask different questions of your character and personality, this was the ideal move.
“He’s not looked out of place. He’s at a huge club and even for someone who’s had the career Joe has, he’s had big gloves to fill.
“I’m glad Joe went to the right side of Glasgow because I’ve had a few mates go to the other side! With Aaron Ramsey, I had to get on to Joe Ledley to say, ‘Have a word with him, what’s he doing?”.
Sinclair feared Hart had lost his hunger for the game after winning five major trophies but is delighted his close friend has proved him wrong at Celtic.
Asked if he suspected Hart had lost his desire, the talkSPORT pundit admitted: “A little bit, yeah.
“Joe’s a wealthy boy and sometimes when you have the wealth he’s got, you can lack that hunger to want to prove yourself again every season or in every game.
“Whether it’s training, games, different clubs, it’s all about proving yourself again. I wasn’t sure Joe had that fight. It looked like he was struggling a touch.
“I wasn’t sure if, because he was so comfortable, that he might just fade away, but he’s proved to me the personality I thought he had is still there, shown his true colours and come back flying.”
Hart teamed up with Sinclair at Manchester City in 2006, when he opted to leave Shrewsbury Town as a teenager.
Sinclair recalled his attitude and talent immediately shone through in training, stating: “As a young man, Joe was fantastic.
“We had David James as first choice, Kasper Schmeichel, who was my boot boy, and we had Joe – not a bad trio!
“Joe was very hard-working and very professional. He wasn’t as chirpy back in the day, but you could see he had personality when we went on nights out socialising and team bonding.
“He’s a big boy as well, so he’s got me out of a couple of sticky situations! Going from Shrewsbury to Manchester City, you don’t do that at 19 if you’re not a special character and talent.
“Joe proved he is. One of the most pleasing things is he’s had his difficult spell – we all have them in life – and bounced back really well to show what he’s made of.”