Joe Hart has lifted the lid on the decision to take a penalty against Aberdeen during today's Scottish Cup semi-final. 

More than a few eyebrows were raised when the experienced goalkeeper stepped up from the spot during the shootout with the Dons this afternoon.

The towering keeper took the fifth pen, with a chance to win it from the spot for his side. 

Just like Ryan Duncan moments before though, the ex-Manchester City and England No.1 stuck the post, as he missed the target.

Hart - whose 'big mouth' got him in that situation - did eventually go on to become the hero for the cup holders, as his save from Killian Phillips saw the Hoops march on to the final on May 25 where they will play either Rangers or Hearts.

"I put myself forward," Hart told Premier Sports. "I've got the biggest mouth when it comes to penalties and they gave me the opportunity.

"There's a lot of trust and a lot of hard work gone into that. I took that penalty with confidence. I missed it, but what a game eh?

READ MORE: What was said about Aberdeen vs Celtic penalty denial

"We should have never been at penalties. We should have put that game to bed. James scored probably one of my favourite goals of the season and I was hoping that would win us the game. But we got it done, that was the most important thing."

Hart made amends by saving Ryan Duncan's spot-kick in sudden death to send Celtic through. And his lack of celebration illustrated just how much relief he was feeling after blowing their earlier chance to finish things.

He added: "That wasn't a feeling of elation, that was a feeling of: 'Wow, I really needed to do that for my team, for my club.' I needed to save that penalty. I felt a lot of responsibility having missed.

"The penalties other than mine, were absolutely superb. Huge moments, huge players in a big season for us. We're excited for this season and working hard for it. I put it on the line. So I had to save that penalty."