The 27-year-old, who is in a relationship with US singer Nicole Scherzinger, is believed to have been spending time in a £1,5000-a-day studio creating his own record and more recently collaborated with R'n'B star Angel.
"I've been doing a lot of writing for different people," The Sun quotes Angel as saying. "The last couple of days I've been working with Lewis. He's doing his thing right now."
Hamilton is believed to have previously worked with rapper Wretch 32.