The pair started dating in November 2015, but have apparently called time on their romance after a difficult few months for Louis, which saw him lose his mum Johannah following a battle with cancer in December (16).
However, the split was said to be entirely amicable, with the former couple still on good terms.
“Louis and Danielle have made the decision to split up but they are still going to be mates," a source told Britain's The Sun newspaper.
"They’re still talking to each other and there is no bad feeling whatsoever."
Shortly after Johannah died, aged 43, Danielle was seen leaving a London hotel with Louis. The last mention of the singer on her Instagram page came on Christmas Eve (25Dec16), the same day Louis turned 25, when she posted a throwback picture of the pair together with the caption: "Happy birthday, my love". She hasn't posted anything on her Instagram for the past three weeks.
And despite their break-up coming just months after Johannah's death, the source insisted Danielle has been of the utmost support to Louis as he grieves.
"It’s really sad because Danielle has been there for Louis through this horrible time," the insider continued. "She has stood by him, remained loyal and continued to be a great support, which is exactly what he needs.
"Sometimes these things just don’t work out and for Louis and Danielle this was the best way forward."
Louis is being kept busy and distracted from the alleged end of his romance with promotional duties in America for his and Steve Aoki's single Just Hold On.
Representatives for Louis have yet to comment on the split allegations.