The UK Sun newspaper is reporting that the couple has been enjoying 'mind-blowing sex' for the past two months.
Liam, 23, and Naomi, 48, has been having trysts in both London and New York.
And the 23 years age gap does not matter to either of them.
A source said: "He can't believe his luck."
However, his friends are worried that Campbell will use him as he is reportedly "head over heels" for the British supermodel.
The relationship comes after he split with Cheryl Tweedy.
Naomi has introduced him to fashion giants such as Hugo Boss as he aims to boost his modeling career.
But a source warned: "People are worried Liam may have had his head turned — and end up heartbroken.
"From Naomi's point of view, being with Liam helps keep her relevant and in the news. She could be seeing him as a plaything before moving on.
"Naomi has a reputation for being tough and getting what she wants."
The pair was spotted together at a Davido Adeleke concert last Monday.
A concert-goer snapped Liam walking behind Naomi, wearing round shades, as they left London's O2 Arena.
Romance rumors first swirled at the New Year when Liam and Naomi partied until dawn at a beach bash in Ghana.
The pair flirted with one another on Instagram and speculation mounted about a romance, with fans dubbing the couple "Laomi".
Campbell is known to date famous men including movie legend, Robert de Niro, 75, and F1 tycoon Flavio Briatore, 67.
Liam was said to have enjoyed a brief romance with US model Cairo Dwek, 21, following his split from Cheryl.
However, the pair could now be getting ready to go public with their romance.
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