Speaking to Breakfast Show host Nick Grimshaw, Fearne said: "Lily Allen blanked me last night. Five times. She blanked me 5 times in a row."
Fearne Cotton and Lily Allen
When teased by Nick's team, Fearne added: "I don't hate her. I got on with her really well last time she was here. We were in a great place. We talked about the kids.
"So I thought, 'Oh, I'll say hi at the Brits.' [But] she looked through me like a pane of glass.
"And she blanked [my boyfriend] Jesse [Wood]. You know my boyfriend is the nicest guy in the world... blanked."
Taking to Twitter to reject Fearne's claims, Lily wrote: "@Fearnecotton I did not blank you. That is simply not true. I didn't see you or your husband."
And she added: "@Fearnecotton any, why couldn't you just come over a say hi yourself?"