Plans are beginning to firm up for the expected Red Hot Chili Peppers-Gnarls Barkley [ tickets ] co-headlining trek that will hit arenas across the US over the early months of 2007.

The collaborative outing, which was announced in October, is taking shape with an early swing through the middle of the country before tilting south and east as the tour moves through the month of January.

The first batch of confirmed dates kicks off Jan. 12 in Oklahoma City, with 17 shows currently on the burner. A March 7 date in Houston closes the outing in its present form; the October announcement touted a three-month run for the two groups, with shows beginning in January. More dates are expected to be confirmed soon, according to the Chili Peppers' label.

The Chili Peppers, who currently are prepping for a late-year run through the arenas of Europe, will embark on a tour of Australia after finishing up the Gnarls Barkley gigs. More information can be found at the band's official website.

The roadwork supports the Chili Peppers' ninth album, "Stadium Arcadium," which surfaced in May. The disc, which follows 2002's "By the Way," moved about 442,000 copies during its first week in stores, enough to earn the group its first No. 1 album on The Billboard 200 chart. Sales have been fueled by leadoff single "Dani California" and follow-up cut "Tell Me Baby."

Gnarls Barkley--featuring Grammy-winning producer Danger Mouse and vocalist Cee-Lo Green--is supporting its debut full-length, "St. Elsewhere," which spawned the mega-hit "Crazy." Last week, the duo issued a deluxe package of "St. Elsewhere"that includes a 92-page booklet and a bonus DVD containing four music videos, as well as live recordings.

Gnarls Barkley will tackle a few appearances in December before heading out on the road with the Chili Peppers. The duo will play a pair of Christmas-themed shows beginning Dec. 7 in Seattle before closing out the year with The Flaming Lips on New Year's Eve in Los Angeles.