Mark Warburton's Glasgow Rangers side are due to take on Hibernian in the Scottish Cup final at the weekend.
Rangers are set to take on Hibernian on Saturday at Hampden Park, with a place in Europe the prize for the victors.
The Ibrox side head into the match as favourites, but Lambert refused to be drawn on which team would win.
“It’s a cup final. It can change on the throw of a dice,” he said. “Hampden is going to be 50/50 in support. I’m not so sure you can say who’s going to win it. It’s such a close call.
“Hibs have had two heartbreaks, and Rangers are on a high - but it’s anybody’s game.”
Chris Iwelumo, who was also in the Sky Sports studio, was more confident with his prediction.
The former Scotland international forward felt that Rangers would have too much quality to win.
“I think Rangers quality will be just too much for them,” Iwelumo said.
Mark Warburton’s side go into the match against Hibernian having had three weeks rest.
Rangers have played a friendly against Tottenham Hotspur in their time off, but they have not had a competitive match in a considerable period of time.
Hibernian, meanwhile, will have to show their resilience if they are to win.
Alan Stubb’s side failed to make it past Falkirk in the play offs, as they aimed to get promoted to the Scottish Premiership.