Watch: Roy Keane spotted taking notes watching Lionel Messi and Co at Barcelona training
Always learning, Roy Keane was fixated on the Barcelona players as they went through a training session in St George's Park in England today.
Ireland assistant manager Keane stared intensely and jotted down notes as Barca boss Luis Enrique put his players through their paces ahead of their pre season clash against Celtic in Dublin on Saturday.
ionel Messi will be part of the Barcelona squad at the Aviva Stadium on Saturday.
Messi, who it was initially thought would not appear after his exertions for Argentina at the Copa America, returned to the Barcelona set up earlier than expected - albeit sporting a new bleached blond hair-style.
Messi will spearhead the Barcelona squad, which also includes other notable stars such as Luis Suarez and Arda Turan, for the visit to Dublin.
Celtic kicked off their involvement in this year's tournament last Saturday when hosting English Premier League champions Leicester City in Glasgow. After a 1-1 draw, Leicester won on penalties.
Cork native Eoghan O'Connell was on target in that game and he will be part of the travelling squad who will take on Barcelona, with tickets still available for the encounter, which has a 6.0 kick-off on Saturday.
This game will be the first of two International Champions Cup clashes in Ireland this summer as Celtic take on Inter Milan in Thomond Park on Saturday, August 13.