The supermodel, 48, and pop star, 25, were caught on video leaving the VIP area at London's O2 Arena following a concert by Nigerian singer Davido.
The Streatham-born beauty looked casual in double denim and a large jacket as she walked ahead with the One Direction singer, wearing a checked jacket, following close behind.
A source told the Daily Star Online : "Liam and Naomi were keen to keep a low profile. They entered and exited the arena via the back door and were quickly whisked up to a VIP suite on Level 3.
"Naomi was more than happy to pose for official pictures inside the venue but didn't have a single one with Liam.
"After the show they left together in the back of a blacked-out green Range Rover and Liam was seen putting his arm around Naomi's waist."
Their apparent date comes after the pair have been flirting on their respective Instagram accounts in recent weeks.
After father-of-one Liam shared a sultry shirtless photo on his page on January 15, Naomi commented: "Beautiful soul," to which Liam responded: "Takes one to know one."
The singer couldn't resist commenting on Naomi's selfie before the Louis Vuitton show in Paris on January 18, writing: "Perfection in a person… don’t give me those eyes."
Liam and Naomi spent New Year's Eve together in Ghanian capital Accra along with her mother Valerie, Vogue Editor Edward Enninful and Sir David Adjaye. In recent weeks, fans have been wondering if Liam and Naomi will becoming the next big celebrity couple, despite having a 23 year age gap.