Country legend Willie Nelson [ tickets ]'s 70th year will be marked by the wizened musician's ongoing tour plans and Columbia/Legacy Records' release of "The Essential Willie Nelson" compilation.

Nelson--who has toured almost incessantly for years--kicks off his latest round of dates with a three-night stand at the New Orleans House of Blues that begins on Saturday night (3/22), and subsequent dates stretch through the end of August.

Book-ending Nelson's April plans are the April 1 release of the two-disc, 41-track "The Essential Willie Nelson" collection; and his April 30th birthday, which lands in the middle of his five-night run at Bossier City, La.'s Horseshoe Casino.

"The Essential Willie Nelson" is billed as the "most up-to-date collection ever," and features tracks that were culled from albums released on nine different labels dating back to 1961, according to Columbia/Legacy.

Included in the set are Nelson classics such as "Night Life," "Crazy," "Blue Eyes Crying in the Rain," "Whiskey River," "Angel Flying Too Close to the Ground" and "Always on My Mind." The collection also features a number of duets, including "To All the Girls I've Loved Before" with Julio Iglesias; "Good Hearted Woman" and "Mammas Don't let Your Babies Grow Up to Be Cowboys," both with Waylon Jennings; "Everywhere I Go" with Emmylou Harris; and recent GRAMMY^®-winning track "Mendocino County Line" with Lee Ann Womack.

Closing out the compilation is the track "One Time Too Many," which is a previously unreleased cut that pairs Willie Nelson with Steven Tyler and Aerosmith.

The set's liner notes will feature testimonials from nearly 50 "contemporary figures" ranging from former Texas governor Ann Richards, Johnny Cash, B.B. King, Ray Charles, and John Fogerty, to Bonnie Raitt, Kid Rock, Dave Matthews, Billy Bob Thornton, and Bono of U2, according to a press release.

Columbia/Legacy also plan to mark Nelson's 70th birthday by releasing expanded editions of eight classic Nelson albums, four of which--"Willie & Family Live" (1978), "San Antonio Rose" (1980), "Always on My Mind" (1982) and "Pancho & Lefty" (1983)--surface in May.

Additional re-releases of "To Lefty from Willie" (1977), the "Honeysuckle Rose" soundtrack (1980), "Willie Nelson's Greatest Hits (& Some that Will Be)" (1981) and "Tougher Than Leather" (1983) follow sometime this summer, along with a previously unreleased concert-recording taken from "the Willie Nelson archive."