The former Arsenal player was his room-mate for away days.
The signing perhaps came as a surprise to many - as the French midfielder does not necessarily plug any gaps among the Leeds team, such is the breadth of midfield talent in the Leeds squad.
But he will add some steel and real passing ability to the Leeds midfield and that will certainly come in useful for the rest of the season.
Since making the move plenty of his former team-mates have been wishing him well in his new venture.
One a little late to the party was former Arsenal youngster Nico Yennaris. The utility player, who finished last season on loan at Wycombe Wanderers, sent this tweet to his former room-mate:
All the best to my roomie on many away trips @toums20, helped me out a lot whilst he was here. Love brother— Nico Yennaris (@Nico_Yennaris) January 27, 2016
Leeds United will be hoping that this rather surprising deal turns out to be one of the bargains of the January transfer window in the months to come.
If he can ensure Leeds stay clear of the relegation fight than that would be a start.