Adam - and who?

Adam Lambert and Kris Allen. Lambert has had an almost flawless run. Photo / AP

Here's one reason why the final of American Idol is a mammoth three hours long - because Paula Abdul's bumbling comments mean the producers have to add an extra hour to the show.

Still, to be fair to Paula, there are many more songs to be sung, a few slayings from Simon to be witnessed, and no doubt more tears to be shed. The first hour of this epic episode features the two finalists, Arkansas dark horse Kris Allen and hot favourite Adam Lambert from California, going song for song and battling it out to win America's votes.

Then the remaining two hours is the grand finale - screening here 36 hours after the live show in the US - when the winner is announced.

The finalists couldn't be more different. On the one hand there's Adam Lambert, 27, the sometimes brooding, but mostly showy singer who established himself as a favourite early on with a blistering version of Ring of Fire by Johnny Cash (even though judge Simon Cowell didn't like it).

And although he had a scare a few weeks back, when he was in the bottom two after singing Sammy Davis jnr's Feeling Good, Cowell reckoned there was no topping his take on Led Zep's Whole Lotta Love the week after. If Lambert already looks like a pro - that's because he is, having been a musical-theatre performer in the the touring production of Wicked. He also survived being in the cast of The Ten Commandments, a rock opera (with Val Kilmer as Moses) that had a brief run in Los Angeles five years ago. And then there's boy-next-door Kris Allen, 23, who recently, along with his trusty acoustic guitar, did a soulful and gritty version of Kanye West's Heartless which many Idol fans proclaimed to be better than Kanye's version.

Now into its eighth season, American Idol remains the most watched TV show in the US, with an average of 26.3 million viewers, and this week's final looks like it could be one of the most hotly contested yet.

Also, over on TV3 it's the final of Project Runway (Friday, 9.30pm) and it's an all-girl showdown between Kenley Collins, Korto Momolu and Leanne Marshall.

American Idol Final

When: Friday, 7.30pm
Where: TV2
What: The final two in epic battle