John, who knew Paul for over 50 years, was the brother of Linda Eastman 

McCartney, The Beatles legend's first and famous wife who died in 1998.

The singer, 80, paid tribute to the famed lawyer on Instagram on Thursday 

with a picture of the pair doing yoga poses. 

Tragic: Sir Paul McCartney's brother-in-law died aged 83 on Tuesday after 

a short fight with pancreatic cancer

Paul wrote: 'My dear brother-in-law, John Eastman, has passed away. Having 

known each other for over 50 years it is an extremely sad time for me, and 

the good luck to have known in my life. Not only did he help me massively in

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. We had so many fun times together through the years,