The defender, who can play anywhere across the back four, will join for an undisclosed fee on a two-year contract, when the transfer window officially opens on June 10.
Brighton under-23s coach Simon Rusk said: “We are delighted that we’ve been able to acquire the services of Josh for next season.
“He will be an excellent addition to the under-23 squad, and his versatility across the back four will be a key asset.
“We are looking forward to welcoming him into the squad for pre-season, and hopefully he can push on and challenge for a place in our first team.”
The 19-year-old leaves Glasgow after spending five years with the Scottish Premier League champions. During his time with the Hoops, Kerr won the SFA Youth Cup, beating Rangers 3-0 in the final, and also played in the UEFA Youth League, where he came up against Barcelona and Manchester City.
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