The Bitz: Band back in the Fold for single's night party.
Legal Man, from their fourth album Fold Your Hands Child, You Walk Like A Peasant, is launched on May 22.
And the night before, as a special treat for Irish fans, Richard and Chris from the band will be holding the huge party in Belfast's Limelight.
Chris told Bitz: "The boys from Snow Patrol are on the same label as us and we've been to Belfast before because of this connection.
"Richard played with Snow Patrol when he wasn't working on Belle and Sebastian stuff so we thought it was a great idea to come over and DJ for the single launch and have a party."
The band's new album is due out on June 5 and has taken more than a year to complete.
"Re-releasing our first album Tiger Milk gave us a bit of space to make the new album the way we wanted," Chris said.
"It brought in some money for the record company while we were spending money like crazy in the studio."
And as for the single, Chris couldn't be happier.
"I like Legal Man a lot," he said. "I liked it when I was able to play it at my club and people danced without knowing what it was.
"It's had a lot of play on the radio which is quite exciting. And it's a good thing that it's getting played when people are listening to it at work, in their office on a sunny day."
"I'm very happy with the album too. I think the arrangements and the production are a lot better than before.
"It was a long, hard slog but in the end we had things worked out and we were sounding a lot better for taking our time over it.
"I think the album manages to cover a lot of stuff that we're all into but there's never a moment when it doesn't sound like Belle And Sebastian.
"As an album I think it sounds reasonably coherent over all."
After their brilliant Dublin show last year, the band hope to get back to Ireland as soon as is humanly possible. But Chris says it won't be for another few months at least.
"We were meant to be going on the road almost immediately but we haven't been rehearsing for a while as people were involved in putting the finishing touches like artwork and so on to the album.
"And Stuart has had a bit of a virus which has taken him a while to recover from.
"But we hope to tour before the end of the year and Ireland will definitely be included."
Until then we will have to content ourselves with a selection of tunes from Richard and Chris's extensive collection - the essence of Belle and Sebastian if you like.
"I'd say I'm more of a record collector than a DJ," said Chris.
"I love Northern Soul and funk and of course I buy new stuff every week. I have to admit that I spend more time buying records than I do working on my DJ skills."
Chris promises a prime selection of Northern Soul, "dubby funk and psychedelic disco."
And he will be bring a copy of Fold Your Hands Child to slip into the mix.
"David Holmes might be dropping in as well so it will be an interesting night all round. I will have a copy of the new album with me but whether or not I'll be playing it will be a different matter.
"I did try and slip some of the other songs in when I was DJing in Glasgow but Legal Man is the obvious one to dance to.
"There are a couple of other songs with the same kind of feel but I don't know if they're too lyrical to play.
We'll just have to wait to see the mood the crowd is in on the night."