www.gloucesterrugby.co.uk that joining an English club is one of the biggest thrills of his career.
"We both understand that Gloucester is a big project for the next few years and Dean Ryan was very confident in his belief we could play an important role in it," Bortolami said.
"To have that confidence is good for the both of us and we are very excited about the new experience of English rugby, of playing for Gloucester and playing at one of the highest levels in Europe.
"For Italian players to get experience in the English Championship is good for the players and good for the national team because the level of rugby is so high, so competitive and very tough.
"Gloucester is a very strong team with a very strong reputation and we cannot wait to start training and playing.
"In France the rugby is much different but the preparation is better in England and that is something we want to experience very much."
The 25-year-old Narbonne lock has joined Gloucester on a two-year contract while Nieto (29) has pledged his future in a three-year deal.
"English rugby is some of the best in the world," Nieto said. "The game in France and Italy is not that different but rugby in England is faster, of a very high intensity level and tough - it is a challenge I cannot wait to experience."