This might appear weird for approaching you in such an informal way, for all our prior communications have been on a pure official note. However, there is a reason for such an approach. You have been a very supportive and encouraging companion in all of work which we have accomplished together. Should your encouragement would not there in the context, I would never have scaled the heights which I have managed to do so.
This letter is to thank you for your support and encouragement when I needed the most and was even unaware of the need for the kind of support which you rendered. I would also like to exploit the time for apologising that the acknowledgement and the appreciation for your support came so deep in time; when it should have been expressed very early. Thank you for being there for everything an supporting me at all the times,
Your companion and friend,