The Suffolk superstar's Mathematics tour logo (+–=÷x) has adorned the front of the Blues' kits for the last four seasons, with more than 100,000 replicas sold during the recent Premier League campaign. His personally designed pink third strip proved a big hit.
Sheeran purchased a 1.4% stake in his home county club last summer and is set to play three nights at Portman Road next month. However, with his long-running world tour set to end in September, he has decided to let someone else take on the shirt sponsorship for 2025/26 and beyond.
"We secured and signed the deal several months ago and that will be announced imminently," said Town chief Ashton, speaking exclusively to the EADT and Ipswich Star.
"Ed knew about that. He's almost been part of the selection process. Ed and I talked, the board talked, and we didn't think gaming (gambling) was the right fit at this time for this football club. We're delighted with the people involved.
"It's big numbers. If we'd have been a Premier League club again this coming season, it would have been the biggest sponsorship deal outside of gaming in the Premier League. And it will be one of the very biggest sponsorship deals in the Championship."
The 2025/26 season is the last of Ipswich's four-year kit manufacturing deal with Umbro.
Meanwhile, on Sheeran's upcoming gigs at Portman Road (July 11-13), Ashton said: "Ed was quite funny. I remember us being at the training ground about a year, 18 months ago and Ed, knowing when his album's coming out, was pushing me for the concert dates. He obviously could do it at Wembley, wherever, but he wanted to do it here.
"My nervousness was the time slots we'd got because of the pitch. I remember being at the training ground and he went, 'Right, if you don't agree to this today, I'm going to do it with them up the road! (Norwich)'.
"I looked at him and I went 'really?' He said, 'Can we shake on it now?' 'Okay, done'. So we shook on it there and then. He was just having a bit of a banter with me, but we agreed there and then, and then the juggernaut has taken over. Incredible. Sold out three nights almost within an instant.
"This is an incredible opportunity to show Ed as a family member to this club, family member to this community. I can't say enough about him, his support this season, his messages after games, his joining us at games. It's almost, forget he's Ed Sheeran world superstar, he's Ed Sheeran, Ipswich Town fan.
"The gigs will obviously bring additional revenue into the club, which is always important, but I think for me, equally, if not more importantly, it is taking this football club's historic brand further to a global stage.
"I say this to the council, I want the town to be the best version of itself. At times I hear a lot of people talk what the town hasn't got, what we haven't done. But I think with the (Fabio Wardley) fight (on Saturday) and the concerts, Premier League season just gone, we've got something to talk about, to put Ipswich on the global map, and I think we should all be really proud of it."