Manager Ange Postecoglou is keen to strengthen his squad ahead of Celtic’s return to pre-season next week and both Siegrist and Semedo could be in the building by then.

Swiss keeper Siegrist, 30, is a free agent after leaving Dundee United at the end of the season. He has options both in England and abroad but Celtic are set to clinch his signature to compete with Scott Bain as understudy to No 1 Joe Hart. Reports on Tuesday morning claim that Siegrist has been spotted at Blythswood Square Hotel in Glasgow, which is a luxury facility that Celtic often use to conclude transfer business.

Siegrist will take the place in the squad vacated by Vasilis Barkas after the Greece internationalist moved on loan to FC Utrecht earlier in the month.

Alfa Semedo impressed in his first season at Vitoria Guimaraes.

Celtic are also poised to capture the signing of Vitoria Guimaraes midfielder Semedo, according to sources in Portugal.

Diario de Transferencias is reporting that Celtic have agreed a loan deal with a mandatory option to buy with the Portuguese top-flight outfit in a transfer that could cost up to £3.5million.

Semedo, 24, joined Vitoria Guimaraes from Benfica last season and he has impressed in his maiden campaign with the club. A Guinea-Bissau internationalist, Semedo has experience of playing British football after loan spells with Reading and Nottingham Forest in the English Championship.

Celtic are also in advanced talks with Jota, a loanee from last season, over a permanent transfer and hope to conclude business in the coming days.

Celtic transfers: Duo 'close to moves' as hotel sighting gives clue on Ange Postecoglou's business