(Cover) - EN Showbiz - Scarlett Johansson was too "intense" for Sean Penn, according to sources.

Rumours of a romance between the Hollywood beauty and the American actor first surfaced back in January when the pair reportedly hooked up while staying at Los Angeles' Chateau Marmont hotel.

Scarlett was said to have been "besotted" with the actor who is more than 20 years her senior.

After a whirlwind five-month affair, the pair split earlier this month, and now reports have emerged that Scarlett was a little too keen for her former beau.

"Sean is simply not ready for a long-term or very serious relationship, given it's too soon since he and Robin [Wright] divorced. Scarlett's intensity just scared him - which is kind of funny, given how intense Sean is," a source told the Chicago Sun-Times.

The former couple were spotted on a number of dates including a romantic day trip to Mexico. Insiders also claimed that Scarlett had "essentially moved in" to Sean's Los Angeles mansion.

A source close to Sean has now revealed the Oscar-winning actor started to "totally freak out" when "a very emotionally needy" Scarlett moved in.

The stunning star is currently in the process of divorcing Ryan Reynolds. (C) Cover Media