Alberto Contador and Lance Armstrong will train together for the first time on Thursday, their Astana team said.

On Tuesday, the two former Tour de France champs trained in separate groups in a session that began on Sunday on the island of Tenerife.

"We have groups each day, one with the best prepared cyclists and the other with the least prepared," an Astana spokesman said. The two are to train together "in theory” on Thursday.

Astana announced Monday that the 37-year-old Texan would race the Tour de France in 2009, having originally implied his focus would be on a maiden Giro d’Italia. But there have been questions raised over the seven-time Tour champ’s place in the team alongside Contador, who won the Tour in 2007.

Contador, 25, had hinted that he may quit Astana following the signing of Armstrong but later said he had been given assurances that he would remain team leader.

Armstrong, for his part, has said that he would work for the strongest rider. And in a recent conversation with Tour director Christian Prudhomme, the American reportedly said that if he did return to the Tour “it would be above all for the sake of his (anti-cancer) foundation.”