Roy Keane has held "informal talks" about becoming the next manager of Celtic, Republic of Ireland boss Martin O'Neill has confirmed.
Keane pulled out of a scheduled news conference in Dublin on Thursday, with O'Neill announcing the ex-Manchester United midfielder had held talks with Celtic over succeeding Neil Lennon, who left the club last week.
"I'd be disappointed if he's gone, but a club like Celtic is a very big club and these particular offers may not come around often," stated O'Neill, as he stepped in for Keane at the news conference.
O'Neill went on to suggest he hoped Keane may consider combining the Celtic job with his role as the Ireland assistant, but he accepted "that may be difficult."
Keane's odds on being named as the next Celtic boss were slashed earlier on Thursday, with the former Sunderland and Ipswich boss confirming last week that he may consider an approach from the Glasgow club.
"I have a job. Of course I played for Celtic, and it's one of the world's greatest clubs, but I've got a job," Keane told reporters in Dublin. "If anyone ever rings me about work I will speak to Martin and the FAI [Football Association of Ireland] but I'm happy enough and focused on what I'm doing.
"People might see this role as part-time or whatever but I've been busy and I enjoy it. I think it's just speculation and that comes from nobody but yourselves [the media]. I don't think you've heard it from any club sources."
Celtic insisted, however, that Keane is not the only man they are considering, with a club statement saying: "Following speculation concerning the managers position at Celtic, the club can confirm that it is currently continuing its discussions with a number of excellent candidates.
"We will continue this process and select who we regard as the best appointment for Celtic. We will update our supporters as soon as this process is complete."
Former Ireland captain Keane -- who has been working as assistant to O'Neill since last November -- played ten games for Celtic in 2006, before he hung up his boots to focus on a career in management.
While Owen Coyle and Henrik Larsson were believed to be contenders for the Celtic job following Lennon's decision to stand down, Keane has now emerged as the most high-profile target for the Scottish Premier League champions.