Buzz is building for 'Foursome,' a sex-themed talk show set to air on E! and co-starring David Burtka, the partner of 'How I Met Your Mother' star Neil Patrick Harris.

"It's bound to be the hottest, hippest show on E! since 'Chelsea Lately,'" one insider who has seen the pilot tells me.

What will make it so hot is the fact that Burtka, along with ex-'American Idol' singer Kimberly Caldwell and two others, will be talking frankly about their own sex lives. This won't be 'Loveline,' folks.