Sheen, 46, who was replaced by Kutcher, 33, after he was fired from the show earlier this year following his erratic behaviour, was really impressed with the programme but found it odd watching it after spending seven years working on it.
Charlie told Access Hollywood: 'It was a big night for everybody on Monday night - for Two and a Half, for us, for me.
'I think everybody won. I thought the show was really good. I thought [Ashton] was terrific.'
The star thinks the show will be successful without him and says it felt like watching a whole new programme.
Talking about his former co-star Jon Cryer, who plays Alan Harper, he added: 'Jon is Jon. He is a freaking genius. I think [the show has] got a real shot. It felt like a pilot. It felt like a really good pilot.'
The first episode of the series, which attracted around 27.8 million viewers, started with Charlie's character's funeral after he was killed by a subway train in Paris.