Leigh Griffiths has opened up on his one on-the-field Celtic regret.
And it comes from his experiences of facing Rangers in a Hoops shirt.
The former Celtic striker has revealed that not scoring against the Light Blues on home soil is the only thing that really bugs him looking back on his spell at the Scottish champions.
The 32-year-old, who played for Livingston, Dundee, Wolves, Hibs and Falkirk, hit over 100 goals for the Hoops, as well as notching over 50 assists.
And while three of those goals cames against Rangers at Ibrox and the national stadium, he couldn't manage to bag at Parkhead. And that's something that still annoys him to this day.
Speaking on the 26 podcast, Griffiths explained: "My only regret is I never scored an Old Firm goal at Celtic Park. I scored two at Ibrox and one at Hampden. Never at Celtic Park.
"I had one glorious chance against Rangers. It's taken a bobble. Literally the slightest bobble. I was about to smash it past the goalie, it's taken a bobble and it's went clean over the bar.
"The game was done but that was my only regret on the pitch at Celtic. Not scoring against Rangers at Celtic Park."
The forward, who now turns out for Australian side Mandurah City, also opened up on his experience of scoring two free-kicks against England is quick succession.
He said: "It was mad. We were doing ok in the game. England had their superstars playing in the game. It was dogged. We weren't getting a lot of the ball but defending well. Alex Oxlade-Chamberlain scored and it took a wicked deflection by Craigy [Craig Gordon].
"I still don't understand why he does not have a hat on as the sun is beating down on his face. I think if he has a hat on and sees the ball he might get it. But the ball is in the back of the net and he is struggling already to try and block it.
"I see Chris Martin warm-up and strip off and I think 'time's up' but we go with two up front. Time is ticking on. 87th minute and Ryan Fraser goes down. Got the free-kick. Placed it and the sun is in my eyes. I am thinking please hit the target. As soon as it is over the wall I start running. I know it is in. I am just waiting for the net to ripple to start celebrating.
"Muck up my celebration. I try to do a knee slide and the ground is so dry I bounce off my knee and end up doing a forward roll. I am just thinking 'first goal for Scotland secured against England'.
"Stuart Armstrong - who I was with at Celtic - fancied the second one but I was like don't even think about it. I put it down, the ref blows the whistle and as soon as it passes Harry Kane's head I am off again.
"Scoring them was unreal. But if we had held on it would have been unreal. It honestly felt like a defeat when Harry Kane scored. A great finish at the back stick. Side foot, opens it up and boom, goal. I literally dropped to my knees.
"Afterwards I got invited to a wedding of my mates. It wasn't until I walked in the place the place erupted. The boys said 'you got a better reception than the bride and groom'."
