A posthumous album by British singer Amy Winehouse had sold almost 70,000 copies one day after it went on sale and was on course to reach number one, the Official Charts Company said Tuesday. "Lioness: Hidden Treasures" was put together following the 27-year-old's death in July and features unreleased tracks, alternate versions of existing classics as well as a couple of brand new compositions by Winehouse. The 12-song album "is on course to be this week?s number one on the Official Album Chart," the company said. It said almost 70,000 copies had been sold, and Winehouse's record company confirmed that it was currently the top-selling album in Britain. "The album came out yesterday and it's number one -- the biggest selling album in the country," a spokesman for Island Records told AFP. Some of the proceeds from the album will go towards the Amy Winehouse Foundation, set up in the singer's memory to help fund charities that provide help, support and care to young people. Her father, Mitch Winehouse, tweeted that "my heart is sad but bursting with pride" at news of the album's success -- although he admitted to reporters that he could not listen to it because the memories were too painful. "I had to listen to it to approve it in the first place, the whole family did, but after that I can't listen to it. I don't want to bust into tears," he said. Winehouse was found dead at her London home on July 23 following years of alcohol and drug addiction. An inquest in October found that she was more than five times over the British drink-drive limit at the time. Following her death, her second album "Back to Black" -- first released in 2006 -- became Britain's highest-selling album of the 21st century, before being toppled by Adele's Grammy-nominated "21" this week.