The deal is expected to be completed next week although permission has been given for the young striker to take part in The Lions final pre-season friendly at Wycombe Wanderers on Saturday.
"I spoke to David O'Leary and he told me that he was happy for me to go out on loan, and when Millwall came in I was pleased to come here," the 20-year-old forward told Millwall's official website.
"I want to play regular first team football and I'm looking to do well at Millwall.
"I saw the way Millwall played last year, and I thought that this is a team which will suit my style. It's good to have the chance to settle in and get a game before the season proper starts."