36-year-old Dilbag Singh, who was charged with wounding with intent to do grievous bodily harm to Brar, appeared in custody at Westminster Magistrates' Court.
Police said Singh has no permanent address. Two other suspects - 33-year-old Barjinder Singh Sangha of Wolverhamption and 34-year-old Mandeep Singh Sandhu of Great Barr, Birmingham - were slapped with the same charge last month.
They were remanded in custody to appear at Southwark Crown Court on December 7 for a Plea and Case Management Hearing, police said.
Sangha has also been charged with common assault of Brar's wife Meena.
Police yesterday announced two more arrests in the case, saying a 36-year-old man was held in west London on Wednesday while a 55-year-old woman was also taken into custody.
The woman, arrested on suspicion of assisting an offender, has been granted bail on condition of having to return on a future date pending further inquiries.
78-year-old Brar, who led Operation Blue Star in 1984 to flush out pro-Khalistan militants from the Golden Temple in Amritsar, was on a private visit here when he was attacked by four men, suspected to be Khalistan sympathisers, on September 30. The incident took place when he was returning to his hotel with his wife.
Brar suffered a wound on his neck and cheek but his wife was not injured in the attack.
A decorated soldier, Brar saw action in the 1971 War with Pakistan, and was among the first to enter Dhaka when the Indian army forced Pakistani army into surrender.