The X Factor judge will perform a charity set at the Mulberry Inn, Surrey on July 6 next year, Evans revealed on his Radio 2 breakfast show today (November 2).
Barlow told the DJ: "I've played many venues in my life, stadiums, arenas, theatres, I've always dreamed of playing in this venue, which is the only reason I've agreed to it really other than the charity aspect. I can't wait to be in your pub."
The Take That star also invited listeners to suggest what they want from the gig, joking: "If they could give me 24 hours' [notice] that'd be good, but maybe they could do a bit of requests on the night."
Barlow then described the gig as an "absolute pleasure", while Evans revealed that the musician had agreed to the proposal "instantly" and "didn't even think about".
Evans will auction off 30 tables for the 'Dine and Disco' event on Thursday, November 8, with proceeds going to Children in Need.
The previous event saw Sir Tom Jones perform and raised almost £612,000 for charity.
The annual Children in Need telecast will air on the BBC on Friday, November 16.