The pair have been inseparable since they were taken in as stray pups a decade ago, and when an eye infection cost Zac his sight, Lilli became his guide dog.
The pair's owner has moved abroad and they are seeking a new home. Sarah Bussell, of the Blue Cross charity in Tiverton, Devon, said Zac would be lost without Lilli, and the dogs had to be re-homed together.
She said: 'They seem to have an almost telepathic understanding, which is quite amazing to see.
Altogether now...aaaahhh! Let's hope they've found a loving new home by now.