Scotland's favourite Time Lord David Tennant has sent a message of encouragement and support to a former Church of Scotland Moderator who lost his granddaughter to cystic fibrosis.

The message came from Tennant in support of the launch of the Very Reverend Dr James Simpson's new book, 'The Magic of Words', dedicated to his granddaughter Sally Russell, who died just days before it went to press.

Cystic fibrosis is a debilitating genetic disorder that mainly affects the lungs. Russell died from the condition despite undergoing a double lung transplant in 2011.

She was a popular and talented Glasgow University student, graduating with first class honours, and was visited in hospital by Tennant shortly before she passed away.

Dr Simpson has written over a dozen books, including the bestseller 'Holy Wit', and proceeds from 'The Magic of Words' will go towards research into cystic fibrosis.

Tennant sent a message of support to the launch of 'The Magic of Words' in an e-mail which said: "I gather that it is a great read and look forward to doing so as soon as possible. I remember with love and affection my meeting with Sally who has now sadly passed away after her courageous fight with C.F. I honour your huge financial contribution to Research into C.F. Have a great night, Love David."

Dr Simpson is a former Moderator of the General Assembly of the Church of Scotland and Tennant is the son of another former Moderator, the Very Reverend Sandy McDonald.

Mr McDonald - now well accustomed to being referred to mainly as 'David Tennant's dad' - was one of the first to receive a copy of Dr Simpson's new book.

He praised it, saying: "It is a long time since I sat down and read a book from beginning to end in one sitting. I just had to start again and read it with more attention because it spoke to me about so much of life and because it was joyously funny too."

Dr Simpson was minister at Dornoch Cathedral for 21 years before moving south to Bankfoot, near Perth. He said his own favourite words are those which "make him laugh for five seconds and think for ten".

He also confesses to an addiction. "Whereas some people get tunes in the brain I get words and phrases in the brain."

He added: "The comic sense is I believe central to what it means to be human."

The Magic of Words is published by Savage Publishers and available from Waterstones priced £6.95.