Justin Timberlake says Clint Eastwood is a fantastic ''mentor'' on set.

The 31-year-old singer-and-actor stars as a rival baseball scout alongside Hollywood legend Clint in 'Trouble with the Curve' and he bonded with the Oscar-winning actor behind the scenes because he was so supportive.

Justin said: ''Just to watch him lead by example. And I've been working for two decades, and that's a long time, but still I'm so young so it was nice to see a leader like that just come in and lead by example and continue to be supportive of everybody else around them. That was great.

''Clint, he is and he was a great mentor on set - we would play golf every weekend together, so it's kind of funny because we were like actually buds on the movie. And it really helped Clint and myself, it really helped our relationship on film.''

The pop star has starred in hit films like 'The Social Network' since swapping music for acting, but admits he still can't believe his luck at being given the opportunity to star in Clint's producing partner Robert Lorenz's directorial debut.

Speaking to FlicksandBits.com, Justin joked: ''I'm just humble to the process, I really am - I'm not gonna pass up a movie with Clint Eastwood ... I actually volunteered to [get his coffee], but he felt like it made him feel weird, so I didn't.''

'Trouble with the Curve' also stars Amy Adams.