They are just a few miles apart and rivalry between Sheringham and Cromer in north Norfolk has always been intense.
But the crab and the lobster are set to unite again when the Sheringham Shantymen perform alongside Keith Skipper at Cromer Pier Pavilion Theatre.
The shantymen's musical director Brian Farrow said: 'Following on from the last two years when, after much turbulent debate, an amicable relationship was finally established, we thought it would make perfect sense to revisit this union of crab & lobster.'
All profits from the show, on Sunday, October 22 at 7.30pm, which will be the singers' last public performance this year, will be divided equally between the RNLI & the Magdalene Group in Norwich, which raises awareness of sexual exploitation of women and young people.
Booking secretary Chris Dolby said they were 'always made to feel very at home by the pier staff and the wonderful theatre audiences'.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here