Ally McCoist's side head into the last-eight clash as huge favourites to progress, with some fans even eyeing up a shot at the silverware at Parkhead in May.
Rovers have already made the headlines this season after dumping Motherwell and Stenhousemuir from the competition to set up their Gers glamour tie.
And Foster insists the Light Blues will take nothing for granted as they look to move another step closer to cup glory.
He said: "It will be a tough game for us and they have already caused a few shocks and done really well so we'll be well guarded against complacency, but the prospect of playing a semi-final at Ibrox is a massive incentive.
"It would be massive for me to reach a Scottish Cup semi-final as I've only played in one before so far in my career, so it would be a great personal achievement and it would also be amazing for the club and fans. We must be 100 per cent on the ball tomorrow."
If James Ward's side emerge victorious tomorrow afternoon, it would go down as one of the greatest shocks in Scottish Cup history.
Foster was on the wrong end of a painful exit during his time with Aberdeen as they lost 4-3 to Queen of the South in the semis six years ago.
The Doonhamers went on to lose the final to Walter Smith's Rangers and the Ibrox right-back admits the fear of more heartache will prevent him looking too far into the future this weekend.
He said: "Yes, without a doubt [it was the most disappointing game of my career].
"I've been involved in a few defeats to lower-league teams in the cup but all things considered, the semi final of the Scottish Cup and the chance of playing a Rangers team who were struggling to field eleven players because of the volume of games was the sorest one.
"You always learn more from the experiences that are not nice and you realise if you go into a game, any game, and you're not 100 per cent focused or do the job to the best of your ability then you could be on the end of a shock so you do learn more from those games."