The two shared digs in the centre's early days with Glasgow Warriors, when Evans was the regular fixture in the midfield. They will now come together on opposite sides when Glasgow face Castres.
"He was a really good friend of mine and he was there for me when things weren't going that well a couple of years ago when I wasn't playing," said Horne yesterday. "He is a really exciting player, but I'm a different kind of player from him, so I love watching him. I'll just try to make sure I can suppress him this week and hopefully show him a trick or two myself.
"He was a really good flat-mate, so easy going and good fun, but just a terrible cook which was a shame. Luckily we had Chris Fusaro though and Richie Vernon. We had a really good flat that year.
"It was very competitive, all four of us are very, very competitive, whether it was Playstation or pool. So there were some good old-fashioned arguments over the pool table and stuff. It was good fun."
How much fun either of them will have at the other's expense tomorrow night remains to be seen but it will certainly be fiercely competitive as Horne tries to help provide the inspiration for Glasgow to somehow revive their European campaign.
"If you look through our team we've got some fantastic players and we are capable of scoring tries so everyone knows the height of the task ahead of us," he said. "It's a massive challenge, but history is there to be made. We're not delusional about the fact that it is going to be a really difficult challenge but it's one that everyone is really pumped up to do.
"We're going to go out there on Friday night all guns blazing. We're by no means going to go out there and roll over, so we'll take it game by game and see what happens."
For all that Gregor Townsend, Glasgow's head coach, said yesterday that he was "keeping faith with the core of players who were beaten by Munster [last week]" there are still some interesting changes. Horne is partnered at centre by Stuart Hogg but for the second successive week the midfield has been re-shaped with yet another play-maker, Scott Wight, pulling on the No.10 jersey. Ruaridh Jackson and Duncan Weir both wore it in the previous two weeks.
Jackson will play for Dundee HSFP in the British & Irish Cup this weekend while fellow internationalist Weir sits on the back as Townsend tries to find a more potent combination after successive RaboDirect Pro12 matches that have failed to yield a try.
"Following the Connacht game I think we've seen a different player," Townsend said of Wight. "That was the first time he started so after that, coming off the bench against Munster and Treviso knowing he can make a difference, he's looked much more confident. He's trained really well. Right through the summer he's been someone who has organised well, been confident in training and it's about taking that into games.
"Scott's in the attack leadership group. He speaks very well and presented yesterday on Castres and he organises and leads well on the field, just like the other two.
"What he's done is contributed well off the bench. He certainly improved things against Treviso and in the Ulster game and played well from the start against the Dragons. There's only been two games since the Dragons so he's now getting his opportunity again."
His inclusion is also partly down to the nature of the opposition. "It's a big part of your selection, form, how they blend with the players in our team, but also you're looking to deal with the opposition," said Townsend.
"We have a base game that we want to play against any team but we also want to exploit the weaknesses and nullify the strengths of the opposition."
Sean Lamont, the team's most experienced back, is rather surprisingly rested given the need to score tries as Glasgow pursue the bonus point wins that are their only way back into contention for the latter stages. However, high-profile signing Sean Maitland is likely to make his debut from the bench.
That, according to Townsend, is down to the fine form shown by Tommy Seymour and increased competition. That is also reflected in the overhaul of the back-row where Rob Harley alone keeps his place as John Barclay and Josh Strauss are recalled.