"Thank you for all the love and care you have shown my brothers. I didn't know how special they were," Joshua wrote in an Instagram post, accompanied by a picture of the two.
"This is 100 percent hard for me, but I know it's even harder for their parents."
The accident occurred on December 29 in Nigeria, where Anthony Joshua was visiting family and friends. Two people, both trainers and friends of Joshua, died when the car they were traveling in crashed into a parked truck.
The driver and Joshua, who was sitting behind the driver, escaped with minor injuries. The driver has been charged with reckless driving.
