With smash hits and strategic partnerships with Bacardi and Blackberry, the Black Eyed Peas are on the highest-profile tour of their career.

Sitting in an Athens hotel room on a humid summer day in early July, Will.i.am recalls the days when he and his fellow members of the Black Eyed Peas made a collective $150 per show-and were ecstatic about it.

"We would jump up and down because we got paid, even though it meant we had to split it with each other and the band, meaning about $20 a piece," he says."Then we got paid $2,000 for a show. And then I remember the first time we got paid a million bucks for an hour. I was like, 'Wow!' That was only four years ago."

Main: Upclose With Black Eyed Peas

Today, Will.i.am, Fergie, Apl.de.ap and Taboo have much more to be excited about. While other marquee acts are canceling shows and suffering from poor ticket sales this summer, the Black Eyed Peas are in  the midst of their most ambitious concert outing yet, the E.N.D. world tour, promoting the album  of the same name.  The tour is sponsored by partners Bacardi and Blackberry, and promoted by AEG Live.

The "E.N.D." album, released in June 2009 on Interscope Records, has sold 2.6 million copies domestically, according to Nielsen SoundScan. It has yielded a run of Billboard Hot 100 hits including "Boom Boom Pow" and "I Gotta Feeling," which commanded the top of the Hot 100 for half of the 2009 chart year (see story, left).

During 2009, the Peas began touring with international dates, including the Glastonbury Festival in the United Kingdom, and a swing of Australian arena dates promoted by Frontier Touring. This year's trek began with North American arenas in February and continued with European dates in the spring that included four nights at London's O2 Arena, two nights at the O2 in Dublin and three nights at Paris' Bercy venue.

The international tour helped further drive shipments of "The E.N.D.," which have reached 4 million outside the United States with a strong performance in key markets including the United Kingdom, France, Germany, Australia and Italy, according to Tom Land, international marketing director at Universal Music Group International.

Although the Peas have a wealth of hit singles internationally, "I Gotta Feeling" emerged as their signature tune for this campaign, according to Land. The track broke a U.K. record last month by becoming the first download to sell 1 million copies, according to the Official Charts Co. It peaked at No. 1 in Austria, Denmark, Ireland, Italy, Sweden, Switzerland, the United Kingdom, Australia and New Zealand. It also went top five in Germany, the Netherlands and Japan.

The song also became an unofficial anthem for the Portuguese soccer team after coach Carlos Queiroz revealed on national TV that the players listened to the track as motivation before the 2009 qualifying matches for the World Cup. The group's May 30 concert at the Estadio Nacional in Lisbon was effectively a sendoff for the Portuguese team before it headed to South Africa. The Peas also performed at FIFA's World Cup Kick-Off Concert June 10 at Orlando Stadium in Johannesburg.

NEXT: The Peas' U.S. Tour