Example of sponsorship form or letter

Hello,

I am getting married and hopefully will be moving to the UK in july of this year and my fiances father has agreed to be an additional sponsor for me but  none of us (me , my fiance , or her father) know exactly what we must do to have him become an additional sponsor for me so I thought I would ask here for some help.

All the information that we have been reading says all the sponsor needs to do is write down some infomation in a letter and submit it to the consulate when we submit our visa application but I am not sure if  this is true or not  so could someone tell me if there is a form that he must fill out or not and if so where can we obtain it...

Additionally we really dont know what he needs to write in the sponsorship letter so if anyone has an example of a letter that would  be EXTREMELY helpful as well.

TIA,
Mike

In addition to the letter, he needs to show a bank statement to prove that he can support you.

My now father-in-law co-sponsored me when I was applying for my fiance visa.  I am sure other people have worded their letters differently, but basically he wrote that he supported our decision to marry and that he was willing to financially support me until such a time that we were married and I was able to work.  He then wrote that he could be contacted at his home and mobile number if there were any questions.  It was kept very short and was basically 3 or 4 lines long.  He then submitted 3 months worth of bank statements to show he had the money to do this.  PM me if you want actual amounts. 
Good luck!