The 38-year-old former 'Desperate Housewives' star, took to micro-blogging site twitter to clarify that the two are just friends, reported Ace Showbiz.
"As interesting as the rumours are, they aren't true," she posted.
The rumours began to rise after it became public that the American actor had attempted to pursue Longoria while he was dating Stacy Keibler.
Clooney, who ended his relationship with Keibler last month, has dated many popular beauties like Renee Zellweger, Lisa Snowdon and Elisabetta Canalis in the past.