James Brown Biopic ‘Get On Up’ Gets By With Help From a Pair of Famous Friends

James Brown would have turned 81 on Saturday, and while his birthday gives fans cause to celebrate the Godfather of Soul, 2014 marks an especially notable year for J.B.'s faithful.

That's because Brown will get the big-screen biopic treatment in August's "Get On Up," starring rising star Chadwick Boseman ("42") as the funk-and-soul icon and directed by "The Help" helmer Tate Taylor.

The film also makes its way to theaters with some added might behind it courtesy of two of Brown's old friends, and living legends in their own rights, Mick Jagger and Dan Aykroyd.

The Rolling Stones frontman serves as a producer on the project, while the "Saturday Night Live" alum co-stars as Ben Bart, Brown's longtime agent.

Both shared their memories on the "Hardest Working Man in Showbiz" when Yahoo Movies visited the film's Jackson, Mississippi, set earlier this year. Production was wrapping up at the Mississippi Coliseum, which stood in for the Boston Garden, home of a seminal Brown performance in the turbulent days that followed the assassination of Martin Luther King Jr.

"We were good friends, we lit up every time we saw each other," an emotional Aykroyd told us of Brown, who died of congestive heart failure in 2006. "I miss him dearly."

[Related: Chadwick Boseman Conjures the Late Godfather of Soul in 'Get On Up' Trailer]

Aykroyd, who was sworn in as a sheriff's deputy in Jackson the day Yahoo visited the set, has often been credited with helping resurrect Brown's at-the-time fading career when Aykroyd cast the singer in the 1980 comedy hit "Blues Brothers."

"When John Landis and I wrote 'The Blues Brothers,' of course there was no one else who could play that preacher role (the Reverend Cleophus James), so we hired James Brown and that was the first time I met him," said Aykroyd, who subsequently cast the singer in two more movies ("Doctor Detroit" and "Blues Brothers 2000"). Aykroyd also proudly recalled how Brown helped him open five separate House of Blues locations, the concert venue chain the actor operates with Hard Rock Cafe co-founder Isaac Tigrett.

Jagger joined the Universal Pictures/Imagine Entertainment release spearheaded by power producer Brian Grazer ("A Beautiful Mind," "Inside Man") in February 2013.

"It's a bit of an exaggeration to say I was great friends with James Brown," laughed Jagger. "I knew him pretty good. I met him when I was very, very young."

The rock star recounted how finally getting to see Brown, who was rarely on television in the U.K. when he was coming of age, inspired his ultimately famous stage theatrics. "It was a bit of an education getting to see him." The two were often on the same bill as both of their careers exploded in the years that followed.

Jagger's involvement in the filming was hands-on, and hardly the case of a prestigious figure simply "slapping his name on" project for support.

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"He has stories about knowing James Brown and being part of that time," said Boseman, who drew raves for playing another groundbreaking American icon, Jackie Robinson, in last year's baseball pic "42," and was also recently seen in "Draft Day" opposite Kevin Costner. "And he has a sense of music, as well, and how a concert should go and how musical things should happen. So having him on the set is definitely helpful."

Tales swirled on-set of a party one night in Natchez, Mississippi, where the 70-year-old rock star took the reins on an iPod and started an impromptu dance party.

So that's right, the cast was treated to an evening of moves not just like Jagger, but from Jagger.

"Get On Up" opens everywhere Aug. 1.

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