The two, who went out for two years and got engaged, were said to have had a showdown at VIP hotspot Pangea in Puerto Banus.
The Wanted front-man Max launched a furious Twitter outburst at her following the incident.
Michelle, 26, was at the swanky nightclub with new fiancé TOWIE star Mark Wright, 27, when she allegedly snubbed 25-year-old singer Max.
George tweeted a series of posts about the event:
“Don’t let him in”... Soaps don’t have that power kids. Embarrassing. Is that fame? S***. Better chase that one.”
Max later tweeted: “Shouldn't vent things on twitter. Apologies. X”
Michelle’s camp have said that the table was full – and the star did not mean to cause offence.
The couple previously argued over the £10,000 engagement ring Max gave her but had not got back four months after they split.