England hooker Mears won the battle to play in the first Test with the Lions this summer, but then lost his place to Welsh rival Matthew Rees.
Mears has plenty of memoreis of Kingsholm having played his first senior trial for Gloucester. In the end, he committed himself to Bath and has become a permanent fixture over the past 10 years.
"We aren't used to having pre-season games at home at Bath because of our ground. I've played in Edinburgh and in France, but to have such a big local derby match on your own doorstep in pre-season is brilliant. I think the supporters will come in their droves," said Mears.
"Andy and I have played with and against each other for many years and that's how we managed to put on this game. We're pretty good mates on and off the field, although he. obviously spends as much of his life as he can bashing me about on the field."