Hales apologises for 'incredibly disrespectful' blackface photo
Former England batsman Hales says a picture that was published by The Sun shows him trying to pay tribute to rapper Tupac Shakur at a party in 2009.
Nottinghamshire batter Hales knows he has been "incredibly reckless and foolish".
The 32-year-old on Friday once again denied Azeem Rafiq's claim that he had named his dog Kevin, a name the spinner alleged his former team-mate Gary Ballance used as a "derogatory" term to refer to a player of colour.
Hales said in a video posted on Instagram: "With the allegations that have come to light over the last few days, I feel like it's important that I address these myself.
"I'll start with the picture that has appeared in The Sun of me in a fancy dress party in 2009. The theme was musicians and Tupac is, was, always will be my favourite musician so I went as him.
"I obviously realise it is incredibly disrespectful and I want to apologise for the offence that this has no doubt caused. It's incredibly reckless and foolish on my behalf so I want to apologise for that and I want to apologise to the club for the embarrassment it would have caused them
"I guess my 20s was full of mistakes like that, reckless mistakes off the field that cost me, let down family, let down team-mates, let down friends, close relationships I had in my 20s.
"I guess some of those decisions I'll regret for the rest of my life. The last few years, being away from the spotlight a little bit has given me the chance to better myself as a human, keep getting better at cricket but getting better off the field as well. It's something I feel like I've done and am continuing to strive to do.
"With regards to the allegations about the dog, it's an ongoing investigation at the club, so I can't go into that, but I want to reiterate what I said in my statement the other day.
"Finally, I deplore all forms of racism and discrimination. I've been incredibly lucky to play around the world in different backgrounds with players of different races, different cultures and I think it's great our game is so diverse."
Nottinghamshire said the club has "extended the scope of their investigation" into the historic conduct of Hales following the publication the photo.