The 22-year-old spent four months on loan with The Lions last season and readily acknowledges that the time he spent at The Den helped to develop him as a player and become an established member of the first team squad at White Hart Lane. He also admits that he still keeps an eye out for the team's results during the season.
"I still speak to the lads at Millwall," revealed O'Hara to The Metro newspaper. "The experience I had there was a real stepping stone.
"I know a lot of Millwall fans and I used to go and watch them as a boy so wish them all the best."