Male midlife crisis – oh how the clichés abound. Typically there is the purchase of a sports car or motorcycle; the trading in of long-standing wife for a younger model and an enhanced interest in personal grooming and gym-going. But if you're an A-list actor, this mid-life acting out is increasingly taking the form of starting up a band. Enter Tim Robbins: Academy Award winner, political activist and, more recently, musician. Hollywood was shocked when Robbins announced his separation last December from his partner of 23 years, actor Susan Sarandon. It had been thought of as one of the strongest unions in showbiz and it, alongside the collapse of a film project, caused him to re-evaluate his life. "A midlife crisis – I think we all go through something, it's inevitable, and it's unavoidable," the 51-year-old said. "I asked myself the question, 'What is it that will make you happy? What is it you have not done that you will regret not doing?" Robbins later said that his remarks were taken out of context and that the album Tim Robbins and The Rogues Gallery Band wasn't about his split from Sarandon. But whatever the reasons behind his career diversion, he's now following his musical dreams.

Of course he's only one in a long line of middle-aged thespians who have exited stage left to embrace the grittier, sweatier rock 'n' roll lifestyle instead. Russell Crowe (46) continues to plug away with his pub rock band The Ordinary Fear of God, formerly known as Thirty Odd Foot of Grunt. They've been going since the late '90s, although Crowe broke out on his own with a solo album in 2006. Welsh hellraiser and former Sienna Miller paramour Rhys Ifans (43) fronts shouty rock band The Peth, while Billy Bob Thornton (55) enjoys fair to middling success with blues rock. Special mention must also go to Jared Leto. Back in the early '90s, he was the angsty teenage girl's pin-up of choice, as Jordan Catalano in the TV series My So Called Life. Today the 39-year-old languishes in some kind of post-puberty peroxided limbo, with 12 years under his belt as frontman of 30 Seconds To Mars, a pretty dire alt-rock group. Without labouring the point, there's also Steven Seagal, Dennis Quaid and, best of all, The Official Band from TV which includes Hugh Laurie on drums and James Denton (Mike Delfino from Desperate Housewives) on guitar. Granted the latter was formed to raise money for various charities but it's still a group of middle-aged men wielding some instruments.

Despite the natural assumption that anyone with wads of cash, fame and acclaim would choose to pursue an Entourage-like existence, it's not actually too difficult to guess why these actors would choose grungy gigs instead of the red carpet. There's the credibility factor – no one is really expecting them to reach number one, the studios aren't clamouring for a box-office smash, so making the music these actors actually want to make is an artistic, and therefore credible, pursuit. There's also the widely held belief that big-budget films are inherently soulless and commercial whereas anything involving a guitar and a small venue constitutes a quest for authenticity. As Nick Hornby says, "I still maintain that music is the best way of getting the self-expression job done."

The acting/singing crossover has been long established from Frank Sinatra right down to present-day performers like Justin Timberlake, and even though musicians like Mick Jagger and Robert Plant confirm that age is no deterrent to rocking out, there's still something about the middle-aged actor-turned-musician that seems risible. But by all accounts, when Tim Robbins played in Dublin last week, he certainly didn't appear to be a man in the middle of a mid-life crisis. He played a very good gig, and ate in Green Nineteen on Camden Street with his band (trying to look inconspicuous in a hat). And, contrary to rumour, he did not miss an appearance at UCD to accept an honorary life membership from the Law Society because he had overindulged on Arthur's Day. In fact, his management had not confirmed that he would attend at all.

"He was very soft spoken and easygoing and he didn't feel like a film star really – just like any middle-aged guy after a Whelan's gig," says one gig-goer who had the privilege of hanging out with him backstage. "He spoke about it all like it was a genuinely organic musical project and not just the whim of a crazed actor. And he had brown bread on his rider." If you've got to have a midlife crisis, by anyone's reckoning, this is a little more dignified and wholesome than the red Maserati/extra-marital affair route.

The day the music died: five more examples of 'don't give up the day job'

John Waters

Considering the crap time the esteemed journalist had at Electric Picnic this year, we are rather astonished that he'd dip his toes into musical waters at all. But behold! Waters is in a new band called The Prodigals with Johnny Duhan, who explore an ever-changing Ireland via performance and readings. Rock. On.

Richard Desmond

When you're the 44th richest man in Britain and you own Express Newspapers and you publish OK! mag, you can do whatever the hell you want. That might include forming a blues band. But it doesn't mean he should.

Eddie Jordan

F1 what? Michael Schumacher who? Eddie's true, abiding love is rock 'n' roll and he plays drums in Eddie and the Robbers, although you could expect anyone from Damon Hill to Bryan Adams and Roger Daltrey to show up and lend a hand.

Pat Cash

Not content with winning Wimbledon and being the face of hair supplement Viviscal, the keen Aerosmith fan recorded a Led Zeppelin song with John McEnroe (don't think about this for too long) for charity and is even thanked in the notes of an Iron Maiden album. Well, he does have the magnificent head of hair for it.

Craig Doyle

We know he's a keen drummer and that he has his own kit at home, but we'd prefer he didn't share his love of beat with the world on the telly. Probably best that Brendan O'Connor landed that
Saturday-night slot after all.