Sir Paul McCartney has remembered his brother-in-law and lawyer John Eastman for his sense of humour and “supreme” devotion to his family following his death.

The Beatles musician, 80, announced the news on Instagram – sharing a picture of the pair holding yoga poses.

He captioned it: “Having known each other for over 50 years it is an extremely sad time for me, and our families.

“John was a great man. One of the nicest and smartest people I have had the good luck to have known in my life.

“Not only did he help me massively in my business dealings as my lawyer but as a friend he was hard to beat.

“His sense of humour always shone through in everything he did and his devotion to his family was supreme.”

Sir Paul, who became Glastonbury’s oldest solo headliner after celebrating his milestone birthday this year, said the pair had “so many fun times together through the years”.

He added: “There is so much more that can be said of his incredible qualities, but words can hardly describe his passion for life and our affection for this amazing man.

“He will be sorely missed but always held dear in the hearts of those of us who knew and loved him. See ya Johnny!”

Mr Eastman was the brother of Sir Paul’s late wife Linda McCartney, who died in 1998.