CELTIC star Leigh Griffiths has expressed his delight over his return to football after battling depression.

The footballer, 28, took to the social media website Instagram today to thank everyone for the support he received as he struggled with his mental health.

Sharing an image of himself with teammate Scott Brown, he also singled out his girlfriend Caitlyn Melville as well as family and friends for their support.

He said: "What a feeling, walking back out on to the pitch after a difficult spell off.

"Great to be back in amongst it again and the reception I got was incredible.

"Someone said to me “after the darkness, there will be light” they promised me It!

"I didn’t believe them, but that person was right.

"Thank you, everyone, for the support, from Caitlyn Melville to my family, very close friends, Celtic FC and my teammates."

The footballer has been making appearances during pre-season and came on as a substitute in Celtic's UEFA Champions League qualifier on Wednesday against FK Sarajevo which the Hoops won 2-1.

READ MORE: Leigh Griffiths opens up about his battle with 'major depression' after making his Celtic return

Griffiths previously discussed his battle with depression last month.

He said: "It was major depression.

"People might say, ‘what’s he got to be depressed about?’, but there are stressful times and it wasn’t the best of times for me. Other people are going through it as well and it’s the same for anybody, if you are going through depression then you need to open up and speak to people. There are people who can help.

“I did try to battle through it. I had to. It’s my job. I can’t just phone up one day and say I’m not training.

“But that’s why I was grateful to the manager [at the time, Brendan Rodgers, above]. He saw it and he gave me the time off I needed. I’m looking forward to now.

“I never asked for time off. It was Brendan Rodgers who said I needed to get my mind right. So, I have to thank him for that because if I had kept playing I would have done myself serious harm."

He added: "My mental health wasn’t right. A lot of things were playing on my mind. So, I just had to step away from football at that time.

“It hasn’t been there for most of my life. It had been there for maybe a year, a year and a half. It started off slow but then it started to snowball towards the end.

“Brendan saw it in training and he knew I wasn’t right. So, I have taken time off. It has been longer than I expected. But I am just glad to be back pulling the shirt back on again. Physically and mentally, it hasn’t been a cake-walk.

“But it is not just my football life. I’ll have a long life after football. I’ve got kids to look after and family to look after. It is a long life after football and I had to make sure I was right.”

READ MORE: Celtic ace Leigh Griffiths 'taking time out' of football for ‘ongoing mental health issues’

We revealed in December that the Celtic star was taking time out from football. Brendan Rodgers said: "Leigh will be out of football for a little period of time.

"He's had ongoing issues for a number of months. He's reached a point where it's a struggle for him. We are going to give him all the professional help he needs to get him back in a good place."