He has joined Fulham on a free transfer after being released by English Premier League rivals Tottenham at the end of last season following an injury-hit five years in north London.
A spate of hamstring issues disrupted Sessegnon's time at Spurs but he is back at Fulham where he broke through as a teenager in 2016 and went on to make 120 appearances, scoring 25 goals.
The 24-year-old, who can play in a variety of left-sided positions, has put pen to paper on a contract until 2026 at Craven Cottage, with the option to extend by a further year.
He said: "It's amazing to be back. Emotional, as well. It's where it started for me, where everything began, and it's amazing to be back.
"It will always be home for me. I think it had the feeling that it was meant to be, coming back here, so I'm delighted to get it done."
Everton have announced the season-long loan signing of Napoli's Jesper Lindstrom.
The Denmark midfielder only moved to the Serie A side last summer but will now spend a year at Goodison Park, with the deal including an option for the move to be made permanent.
The 24-year-old has 16 senior international caps and won the Europa League with Eintracht Frankfurt in 2023.
Newly-promoted Southampton have signed two Brazilians as they strengthen up for the new season, which opens next month.
Wellington, a left-back, and forward Juan will join Southampton in January - the midway point of the English season - from Sao Paulo after signing pre-contract agreements with the south coast club.
Having made his senior debut for Sao Paulo in 2020, 23-year-old Wellington has made 150 appearances for the club. He has also represented the Brazil Under-23s.
Juan, 22, has represented Brazil's under-17s and under-18s and made 80 appearances for Sao Paulo.
Brentford have sold Wales international Fin Stevens to promoted Bundesliga side St Pauli for an undisclosed fee.