The British actors will star in the upcoming sci-fi sequel from JJ Abrams, set for release next year.
"Benedict is such a good guy, he's a really sweet person and I love that he's getting this success because he's also a great actor," Pegg told The Sun.
"I worked a lot with him on Star Trek. He is part of the threat in the film."
Pegg joked that Cumberbatch has boasted about his recent 'Sexiest Man' poll win, as voted by the tabloid's readers.
"Oh, he told me he had won all right. We went out one night and he said, 'You'll never guess what, I am The Sun's sexiest man'. And I was like, 'That's amazing. That is so cool'."
Pegg also revealed that avoiding alcohol in the past two years has helped him keep fit for Hollywood movie roles.
"I find it easier to keep fit if I don't drink. I have given up for two years and I don't miss it in the slightest.
Photo gallery - Star Trek 2 on-set pictures:
Copyright: Rex Features On Location News
"I was starting to do Mission: Impossible - Ghost Protocol, which required more of a physical contribution and drink is so many empty calories.
"I also want to be able to wake up fresh in the morning and play with my kid. You can't be a present parent and drink, unless you take it in turns to lie in until 11 every morning."
Simon Pegg recently revealed that Benedict Cumberbatch will not play the villain Khan in Star Trek 2.
Star Trek 2 is due for release on May 17, 2013 in the US and the UK.
The 42-year-old actor will next be seen in A Fantastic Fear of Everything, which is released in the UK on June 8.
Watch the trailer for A Fantastic Fear of Everything below: