Thanks Suresh for your response!!!
I've already tried both the options and putting a textbox on that grey cell will the last option I use in case if we can't figure out the proper approach.
And if we do the "Cell background color transparency" to 100% then it will apply to all the cells and that's what I don't want. Because we have corporate color policies and because of that I just need to color that particular cell as per the policies.
Thanks for your help!!!