Two and a Half Men wraps a dozen years of comedy with series finale Thursday

There's been plenty of comedy onscreen and tons of drama behind the scenes.

It all comes to an end Thursday as Two and a Half Men, the remarkably durable hit CBS sitcom, wraps its 12-season run with a one-hour series finale (9 p.m. ET).

Funny or not, the conclusion will answer this burning question: Will former series star Charlie Sheen make a conciliatory guest appearance, as rumoured, four years after his rancorous firing?

Rife with jokes about genitalia and bodily functions, the series premiered in September 2003. It was built around Sheen and his real-life image as a freewheeling bachelor. The character Sheen played, Charlie, flush from writing jingles, shared his cushy beach-front house with his uptight brother, Alan (Jon Cryer) and Alan's young son (Angus T. Jones).

By this season, Jones (grown to full manhood) had left the series.

So had Sheen, years before, after months of show-biz turbulence fuelled by scandalous behaviour on Sheen's part amid high-decibel clashes between him and Men co-creator Chuck Lorre.

Sheen was fired from the show in March 2011. That spring, he roared back with a bizarre nationwide tour of live appearances billed as My Violent Torpedo of Truth/Defeat is Not An Option.

That fall, Charlie was reported dead (from falling in front of a Paris subway train) as Ashton Kutcher joined the revamped sitcom as a billionaire internet entrepreneur who took over the house.

By this season, the series had recovered its two-and-a-half-men standing as Kutcher's character, Walden, adopted a little boy — after pretending to be married to Alan to boost his case that he could offer the child a stable, two-parent home.

In last week's episode, Alan proposed to his on-again-off-again girlfriend, Lyndsey (Courtney Thorne-Smith), who accepted, and Walden almost popped the question to Ms. McMartin (Maggie Lawson), the sexy social worker who handled the adoption.

On the finale, will Alan and Walden go through with marriage (to people other than each other)?

And will Charlie rise from the dead?