The West Ham United legend is a big fan of Jack Wilshere.
Boyata claimed injury prevented him from playing for Celtic against AEK Athens.
Celtic face AEK Athens tonight in their Champions League qualifying tie.
John Hartson has looked ahead on Twitter to Celtic's Champions League qualifier against AEK Athens.
John Hartson has hinted that Celtic should start with centre-forward Leigh Griffiths against AEK Athens.
John Hartson praised Celtic after their win in Champions League qualifying.
Celtic are light on central-defensive options for tomorrow's clash with Rosenborg.
Steven Gerrard’s Glasgow Rangers will not beat Celtic to the Scottish Premiership title, says John Hartson.
Celtic’s Kieran Tierney has been linked with moves away.
John Hartson raves about Celtic striker Moussa Dembele.