"I felt like my 'bucket list' bucket was full, and I couldn't want for anything," Toby Keith recalls, looking back on his lengthy career. "I'm so blessed, and I couldn't think of one thing."Reco

However, recently -- just when Keith thought he'd achieved everything he'd set out to do -- the country star developed a friendship with legendary actor and filmmaker Clint Eastwood, and ultimately wrote a song to be included in Eastwood's new movie, The Mule. Keith says the experience made him re-think the scope of his goals, and reminded him that nothing is off-limits or impossible.

"This Clint Eastwood thing made me get a bigger bucket!" he jokes.

While the project may have reinvigorated his sense of possibility, Keith has long been willing to take chances in his career. He dates that trait back to the time he walked away from his deal at Mercury Nashville and signed to then-independent label DreamWorks Records in 1999, after Mercury refused to release a then-new single, called "How Do You Like Me Now?!," that he brought to the table.

"I talked them into dropping ["How Do You Like Me Now?!"] at Mercury, took that album and walked across the street. I was right, you know?" Keith explains. "I had everybody disagreeing with me. Once I took that album across the street, and I was right, and it was [ACM] Album of the Year -- I was pretty fearless after that."

The singer took a major risk in walking away from his label home, but he knew he had to fight for his song. The success he found with "How Do You Like Me Now?!" gave Keith renewed confidence in his musical instincts.

"It was really hard to tell myself 'no' after that, you know what I mean?" he goes on to say. "Once I signed with DreamWorks and I sold [the song] to them and I was right -- then it was like, 'Now I know what I need to do. It's clear as a bell now.'"

The lesson Keith learned by putting out that track applies to life in general, even beyond the music industry: "Be yourself," he adds. "Go do what you do and let it land where it lands. Quit trying to be a turntable success."

Toby Keith + More Country Stars' First Tweets

How Well Do You REALLY Know Toby Keith?