Dr. Heywood Floyd: 
Good day, gentlemen.  This is a pre-recorded briefing made prior to your departure.  In which for security reasons, of the highest importance, has been known onboard during the mission, only by your HAL 9000 computer.  
Now that you are in Jupiter's space and the entire crew is revived, it can be told to you.  18 months ago, the first evidence of intelligent life off the Earth was discovered.  It was buried 40 feet below the lunar surface, near the crater Tycho. 
Except for a single very powerful radio emission, aimed at Jupiter, the 4 million year old black monolith has remained completely inert.  It's origin and purpose....still a total mystery.