Half season tickets holders are able to bring a friend or family member to the club's game against Barnsley at The Valley on February 1st.
More than 2,700 free tickets have already been snapped up by Charlton supporters for the game.
Tickets for the visit of the Tykes went on sale earlier this month with the Addicks' new owners, East Street Investments, offering all full season ticket holders an additional free ticket to bring a friend or family member to cheer on Lee Bowyer's boys and experience The Valley.
After feedback from supporters and Charlton Athletic Supporters Trust the deal has now been extended to half season ticket holders.
Supporters in possession of a valid full Adult, Over 65, U21 or student price [or the corresponding disability price class] 2019/20 season ticket or half season ticket will be able to redeem one free ticket for the fixture against Barnsley.
Fans having problems redeeming the ticket can use this instructional video.
There is no guarantee that you will be able to redeem your free ticket in the seat next to your current season ticket seat. Due to the limited number of seats in each zone, free tickets will be allocated on a first come, first serve basis.
A booking fee of £1.50 will have to be paid for each free ticket redeemed.
Season ticket holders in Zones 1, 2 and 3 will only be able to redeem their free ticket in the same pricing zone which they are sat in. Once tickets have been redeemed in each price zone, there will be no more available. Please note that full season ticket holders and half season ticket holder will not be able to move their seat for the game.
Season ticket holders sat in Zone 4 will be able to redeem a ticket on either Zone 3 or Zone 4 due to the limited number of seats available in Zone 4.
The offer lasts until midnight on Wednesday, January 29th and so supporters are urged to book as soon as possible to avoid disappointment.