Eddie Wolecki Black says becoming Celtic Women's new head coach was too big an opportunity to miss as it was announced he is to leave Motherwell.
The 53-year-old has led Well to the top of Scotland's second tier and will remain in charge until August in the hope of securing promotion.
"I had a very difficult decision to make and I leave with a heavy heart," he told Well's website.
"It's a big opportunity - a huge honour to join a club of Celtic's stature."
Celtic lie third in the Scottish Women's Premier League, behind Glasgow City and Hibernian, while Well have a 13-point lead over Kilmarnock in SWPL2.
"I'm staying with the team with a view to staying with them until the title is won," Wolecki Black said. "They are in a very good position and I want to see it through.
"We did a lot of recruitment in the summer and there's so much talent in the squad."
Wolecki Black, who was a striker with Montrose and also managed the club, made his mark in women's football during a 14-year tenure with Glasgow, leading them to four league titles, four League Cup and four Scottish Cups.
He moved back into the men's game as manager of Airdrieonians but suffered a stroke in March 2016.
Now, following his battle to regain fitness and after eight months with Motherwell, he is looking forward to tapping into the resources at Celtic Park.
"I know that Celtic has a real commitment to women's football and in developing its team further - and this is something I really wanted to be part of, at one of the world's great football clubs," he told Celtic's website.
"I know the team already has some real qualities and I will be aiming to build on these."
Celtic commercial director Adrian Filby revealed that David Haley, who has been in charge for five years, would now concentrate on "our highly-regarded Girls' Academy", while Edward Gallagher would take temporary charge of the first team.
"Eddie has a great reputation within football as a coach and we believe that the talented squad of players at Celtic will benefit from his experience in the second half of this season and beyond," he added.