As reported by our sister title the Chichester Observer, the Bognor midfielder has been in talks to join John Coleman's side this summer.
Now his brother and Rocks team-mate, Ashton has revealed on social media that Leigh is heading for the Wham Stadium.
He wrote on Twitter: ‘Time has come to say tala to the little bro. One of us had to become a pro but I’m over the moon for it to be you.
‘Get up there, and smash it like I know you will I love you mate.’
Leigh moved to Bognor from Baffins Milton Rovers last summer.
Although the Rocks' Isthmian League campaign was curtailed amid the coronavirus crisis, the former Priory School pupil impressed duly to earn a switch to Stanley.
His move means Accy – who ended Danny Cowley’s side’s play-off hopes on the final day of the 2020-21 campaign – have poached Leigh from Pompey's own doorstep.
He's the latest non-league player to be lured away from the Blues' patch.
Jonah Ayunga left the Hawks for Bristol Rovers 12 months ago after former boss Kenny Jackett turned down the opportunity to sign him.
The striker netted a double as the Gas beat Pompey 3-1 at the Memorial Stadium in February.
Meanwhile, Ethan Robb was signed by Brentford after being spotted playing for Bognor – although he'd been released from Fratton Park at the end of the 2019-20 season upon the culmination of his two-year academy scholarship.