Ulster have completed the signings of fly-half Niall O'Connor and hooker Rob Herring for the 2012-13 season.
O'Connor returns to his native province after spending one year with Connacht while Irish-qualified Herring comes to Belfast from Western Province.
During his previous spell with Ulster, O'Connor made 51 appearances and scored 212 points.
The pair will add further depth to the squad, with Tommy Bowe and Roger Wilson having already agreed to rejoin Ulster.
The fly-half was part of the Connacht side which defeated Harlequins 9-8 to secure their first-ever victory in the Heineken Cup last season.
The 24-year-old will compete for the fly-half position with Paddy Jackson and Ruan Pienaar following the departure of Ian Humphreys to London Irish.
South African Herring enjoyed a brief stint with London Irish before returning to his native country.
The 22-year-old joined the London Irish Academy in 2009 and made his senior debut against Northampton in May 2010.
He will provide competition for Ireland international Rory Best, Nigel Brady and Niall Annett.
"The additions of Niall and Rob will further enhance our ability to compete over the course of a gruelling season," commented Ulster Director of Rugby David Humphreys.
"Niall went away and gained a year's experience playing with Connacht and he has now come back to challenge Paddy and Ruan for the number 10 jersey.
"Rob is a typical South African forward who is very physical and is an accurate set-piece operator. He is Irish-qualified and is a very ambitious individual who will thrive in our training environment," added Humphreys.
"I got a fair bit of game time with Connacht, gained more experience and feel I have improved as a player over the past season," said O'Connor.
"But when the possibility arose to move back to my home club, I thought it was a fantastic opportunity as Ulster are one of the best sides in Europe," he said.
"It was great watching my mates do so well in the Heineken Cup last season.
"I'm not thinking too far ahead but I'll get pre-season under my belt and then hopefully I'll get a run out in the friendlies and take it from there," he concluded.