(Cover) - EN Showbiz - Scarlett Johansson and Sean Penn are believed to have ended their romance.

The Hollywood stars reportedly dated for several months, after Scarlett announced she was splitting from her husband Ryan Reynolds last year. Scarlett and Sean were spotted enjoying several romantic dates and even attended a White House Correspondents' dinner party in Washington together in April.

However, rumours the romance was on the rocks surfaced when Scarlett failed to attend the Cannes International Film Festival with 50-year-old Sean last month, where he was promoting his new movie The Tree of Life.

According to People magazine, the pair are no longer dating and a reason for the split is not yet known.

Scarlett, 26, is currently in New Mexico where she is shooting scenes for new movie The Avengers, which will see her reprise her role as Black Widow.

Even though Scarlett and Sean insisted they were just friends, it was recently claimed the beauty had moved into the actor's Malibu home.

They are also believed to have enjoyed a holiday to Mexico in January and the pair attended Reese Witherspoon's wedding to Jim Toth together in March.

Representatives for the stars have declined to comment on the split rumours. (C) Cover Media