Pleasant pop singer-songwriters Gavin DeGraw and Colbie Caillat are teaming up for a co-headlining summer tour that also features Andy Grammer as an opening act. The month-long trek begins in late May in Simpsonville, South Carolina and is currently scheduled to wrap up with a June 29 show near Chicago.

Caillat responded, "SO pumped 4 this tour!," after Grammer tweeted the news, "Spring Tour Baby!!! Two of my favorites :)"

DeGraw, best-known for hits 'I Don't Wanna Be' and 'Not Over You,' is currently moving out of his comfort zone on 'Dancing With the Stars,' in addition to promoting his most recent album, 'Sweeter.' Caillat is supporting her 2011 release 'All of You' and single 'Brighter Than the Sun.' Grammer's self-titled debut hit No. 1 on Billboard's Heatseekers album chart last year.

Because these three seem to genuinely like each other and their musical styles are so similar, we're betting this tour will see a lot of on-stage duets. Grammer and Caillat sang 'Fine By Me' together when they toured together back in October.

Colbie Caillat + Gavin DeGraw Tour Dates:
5/25 - Simpsonville, S.C. | Charter Amphitheatre at Heritage Park
5/26 - Biloxi, Miss. | Hard Rock Hotel
5/27 - St. Augustine, Fla. | St. Augustine Amphitheatre
5/29 - Pittsburgh, Penn. | State AE - Outdoors
6/1 - Philadelphia, Penn. | Penns' Landing - River Stage
6/2 - New York, N.Y. | Rumsey Playfield
6/5 - Bethlehem, Penn. | Sands Bethlehem Event Center
6/7 - Pomona, N.Y. | Provident Bank Park
6/8 - Norfolk, Va. | Town Point Park
6/9 - Vienna, Va. | The Filene Center at Wolf Trap
6/10 - Baltimore, Md. | Pier Six Pavilion
6/12 - Raleigh, N.C. | Raleigh Amphitheatre
6/13 - Atlanta, Ga. | Chastain Park Amphitheater
6/14 - Charlotte, N.C. | Time Warner Cable Uptown Amphitheater
6/17 - Fayetteville, Ark. | Arkansas Music Pavilion
6/19 - Bee Cave, Texas | The Backyard
6/21 - Lake Charles, La. | L'Auberge Du Lac Casino Resort - Pool Stage
6/22 - Thackerville, Okla. | WinStar Casino
6/24 - St. Louis, Mo. | Peabody Opera House
6/26 - Sioux City, Iowa | Orpheum Theatre
6/27 - Apple Valley, Minn. | Weesner Amphitheater
6/29 - Highland Park, Ill. | Ravinia Festival