Conservative leadership hopeful Michael Gove has said he "deeply regrets" taking cocaine "on several occasions".
The Environment Secretary said he used the drug 20 years ago and branded it "a mistake".
It comes after fellow Tory contender Rory Stewart apologised for smoking opium at a wedding in Iran.
Mr Gove told the Daily Mail: "I took drugs on several occasions at social events more than 20 years ago.
"At the time I was a young journalist. It was a mistake. I look back and think 'I wish I hadn't done that'."
He added: "It was 20 years ago and yes, it was a mistake. But I don't believe that past mistakes disqualify you."
Mr Gove, MP for Surrey Heath, said it would be up to his colleagues whether he should be leader, but added that he did not "act with an eye" on going into politics when he was younger.
"The question now is that people should look at my record as a politician and ask themselves 'is this person we see ready to lead now?'," he said.
Speaking to Sky News last week, International Development Secretary Mr Stewart said: "I think it was a very stupid mistake and I did it 15 years ago, and I actually went on in Iran to see the damage that opium was doing to communities."
He added: "I've seen it as a prisons minister. It was something that was very wrong, I made a stupid mistake.
"I was at a wedding in a large community meeting and somebody passed this pipe around the room and I smoked it - I shouldn't have done, I was wrong."
Meanwhile, the race to succeed Theresa May as Prime Minister has stepped up a gear following the submission of her resignation on Friday.
Education Secretary Damian Hinds has given the Gove campaign a boost by lending his support - becoming the second Cabinet member to back the Environment Secretary.
He told The Times: "The next prime minister has to do two sets of things.
"First: deliver Brexit, craft our new relationship with Europe and set our place in the wider world.
"Second: construct a compelling domestic agenda for the whole UK, that spreads opportunity, grows wages and continues the improvement of our public services.
"Michael Gove has the mix of abilities to do both."