The 52-year-old music mogul is proud of the boy band - who shot to fame on his singing competition show 'The X Factor' in 2010 and are signed to his SyCo record label - and revealed he thinks their second album 'Take Me Home' is "fantastic".
Simon tweeted: "I heard most of the new one direction album today. It really is a fantastic album. I can't wait for you guys to hear it.
"When you hear or see something you have been a part of which is fantastic you realise how important your partners are. I am very lucky. (sic)"
The 'One Thing' hitmakers are set to release the LP in November and first single 'Live While We're Young' is already proving popular with their loyal fans, breaking a world record with 8.24 million views on VEVO within 24 hours of being posted online.
Simon tweeted last week: "Glad you all seem to like the new one d single. You are amazing fans. (sic)"
The group - Niall Horan, Zayn Malik, Liam Payne, Harry Styles, Louis Tomlinson - recently admitted their second album is a big departure from their first pop offering.
Niall said: "It's a million miles away from our old album. It's a bit more of a live-sounding album. The drums are a bit harder."