Kutcher has 'tense' first day on set

Ashton Kutcher's first day on 'Two and a Half Men' was very tense.

The 33-year-old actor – who replaced troubled star Charlie Sheen on the CBS sitcom after he was fired following a public spat with the show's creator Chuck Lorre – first appeared on set on Monday but the atmosphere was so strained onlookers could "cut the air with a knife".