Full-back Chris Paterson was ruled out for the trip to Belfast with an ankle problem paving the way for Thompson - grandson of celebrated rugby commentator, Bill McLaren - to make his full debut for Edinburgh.
As a result, Thompson says he is saddened by Paterson's injury, but adds he, and his famous tipster dad, are both thrilled by his call-up into the starting line-up.
Thompson said: "I'm really looking forward to it. It is a shame that Mossy (Paterson) is out injured and I feel for him.
"But it has created an opportunity for me and I'm looking forward to starting for Edinburgh and playing as well as I can.
"I gave my Dad a wee text earlier on and he replied: 'Well done son!'
"Unfortunately he can't make it over to Belfast, but I'm sure he has already checked the odds on me scoring the first try!"
After making his Magners League bow as a replacement at Leinster last season, the 23-year-old had to wait 12 months before sampling his next taste of professional rugby.
But National Academy graduate Thompson says he believes he has matured into a better player over the past year; largely thanks to his time on the IRB World Sevens circuit and playing with his club team, Heriot's
He added: "I learned a lot in between my first game for Edinburgh and my second game, largely thanks to the education I've received in the Scottish Rugby set-up.
"I have developed physically over the 12 months and I've been away with Scotland Sevens which has also helped my game.
"Coming on as a replacement over the past two games has really given me an insight as to where you need to be in order to play Magners League rugby and I feel like I'm a lot better equipped to do that now.
"Heriot's has also been a great place for me to develop my rugby and you only have to look at the number of players who have gone from there on to become capped internationalists.
"Bob McKillop and George Breckenridge - the coaches - have really helped turn the place into a great breeding ground for up-and-coming players.
"They helped John Houston as well and I would say they have been a big help to me."
Former Heriot's team-mate John Houston joins Thompson in the back-three after successfully recovering from a long-term pelvic injury.
Houston, last season's Newcomer of the Year, endorsed Thompson's promotion into the number 15 shirt and hopes they will rekindle their on-field understanding.
Houston said: "It is good to see Jim get a start because he is a really gifted player.
"I've enjoyed playing alongside him every time we've played together, so I'm looking forward to linking up with him again."
David Blair makes his first start of the campaign in a half-back combination with elder brother Mike who was rested for the match at Rodney Parade.
Andrew Kelly - nearing his 100th appearance for Edinburgh - is handed the number two shirt with regular first choice hooker Ross Ford named amongst the replacements.
In the second row, Ben Gissing returns to the starting line-up at the expense of Craig Hamilton while on the bench, National Academy flanker Chris Fusaro could make his debut for Edinburgh.
Lock Steve Turnbull (fractured ankle) is expected to be sidelined for a lengthy period of time while Paterson (ankle) and Alan MacDonald (eye) join Simon Webster (hip), David Callam (hip), Simon Cross (ribs) and Roland Reid (knee) on the injury list.
Meanwhile, long term absentees Ben Cairns (knee ligament), Ross Rennie (knee), and Matt Dey (shoulder) are still recovering.
Edinburgh Rugby Club squad to play Ulster at Ravenhill (Friday 3 October, kick off 7.30pm)
15 Jim Thompson
14 John Houston
13 Hugo Southwell
12 Nick De Luca
11 Mark Robertson
10 David Blair
9 Mike Blair (captain)
1 Allan Jacobsen
2 Andrew Kelly
3 Gavin Kerr
4 Jim Hamilton
5 Ben Gissing
6 Matt Mustchin
7 Allister Hogg
8 Scott Newlands
Substitutes: Ross Ford, Geoff Cross, Craig Hamilton, Chris Fusaro*, Greig Laidlaw, Phil Godman, Calum MacRae.
* = denotes National Academy player
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