By SABC Sport
16th August 2023
The midfielder made it known to his club on Monday that he favoured a move to Stamford Bridge over Liverpool, who had had a similar bid accepted, with a deal having been reached on Tuesday night for him to join the west London club.
Lavia will now undergo a medical in advance of becoming the eighth first-team signing the club have made this summer.
He made 29 Premier League appearances last season in what was his debut top-flight campaign, after joining Saints from Manchester City last summer.
The club have also agreed to pay Crystal Palace winger Michael Olise's £35m release clause, paving the way for the France Under-21 international to join Lavia at Stamford Bridge.
It takes Chelsea's spending this week to over £200m following the British record capture of Brighton's Moises Caicedo for a potential £115m on Monday.