However, the 34-year-old former Rangers, Cardiff and Burnley striker is ready to give everything when he faces another of his former clubs, Dundee United, in their Clydesdale Bank Premier League clash in Paisley on Saturday.
As soon as that match is over, Thompson will return to some sports psychology techniques he has picked up over the years to get himself in the best frame of mind for the trip to the national stadium.
"We obviously have tomorrow's game against Dundee United and have to show a reaction to losing to Dundee during the week, to give belief and confidence back to the supporters for next weekend," he said. "But there is no doubt you would be lying if you said you weren't thinking of next weekend.
"It has certainly been at the forefront of my mind for quite some time. I think about it on a daily basis. I am willing to admit that basically it is consuming most of my head space and has been for weeks and I am not scared to admit that.
"I have been visualising plenty of things and they are all positive. Visualising is an important part of preparation for sport and in my head I have got quite a few powerful visions."
Boss Danny Lennon, though, insists the Dundee United match will not simply be a warm-up for the cup final.
"I won't be resting anyone," he said. "It is not a cup final preparation, it is all about getting three points. The players will have one eye on next Sunday but rest assured we will get the right application and right attitude come three o'clock on Saturday."
Lennon revealed that Lee Mair is facing a race against time to be fit for Hampden. The Buddies defender picked up a stomach injury in the 2-1 SPL defeat by Dundee in midweek which is causing the Paisley boss "real concern."
Lennon revealed Jim Goodwin's calf complaint makes him "touch and go" for the match against Dundee United while Gary Teale is making good recovery from his abductor problem and Thompson will shrug off a tight groin.
- Sports & Recreation
- Dundee United