Wales captain Gareth Thomas will join up with the Lions on Tuesday after Toulouse lost to Stade Francais in the French championship semi-final. Lions coach Sir Clive Woodward had been locked in negotiations with Toulouse about the 30-year-old's release.
He wanted Thomas to fly out to New Zealand after the Heineken Cup final on 21 May, but Toulouse wanted to retain him until their championship had ended.
Jason Robinson will fly out on Thursday after staying with his pregnant wife.
Woodward said: "Gareth Thomas is a world-class player who has had a fantastic season behind him.
"I have no doubt he has an enormous contribution to make to the tour.
"With him and Jason Robinson coming out, it is a double boost for us."
The Lions squad will reach its full complement of 45 players when
Robinson arrives in New Zealand on Thursday.
Thomas will now be in contention to play against New Zealand Maori on 11 June, while Robinson will be in the frame for selection against Wellington on 15 June.
Toulouse head coach Guy Noves had been desperate to end Stade Francais' two-year dominance of the French championship.
But his side's title bid was ended by a 23-18 defeat by Stade.
With Thomas's club commitments now at an end, he is making preparations to
leave for New Zealand on Monday.