There are two shows for the price of one at “Player Kings,” in which the director Robert Icke has combined both of Shakespeare’s “Henry IV” history plays into a self-contained whole.

The production offers a compressed version of the royal accession story that, in this version, runs nearly four hours. It is an opportunity to experience Ian McKellen’s unbridled love of performance. At 84, the production’s leading man possesses an energy and vigor that belie his years.

“Player Kings” — which runs at the Noël Coward Theater through June 22, before touring England — is the latest in a wave of recent high-profile Shakespeare productions in London. Uniquely among the other great British theater actors of his generation, McKellen still returns year after year to the stage, recently tackling Lear for a second time and playing an octogenarian Hamlet.

Perhaps inevitably, there’s a feeling of the star vehicle to this production. In the “sweet creature of bombast” that is this play’s John Falstaff, McKellen has an especially juicy assignment — an outsized character whose appetite for life matches the actor’s own gusto. We’re told that the ample Falstaff hasn’t seen his own knees in years, and when he sits, it looks as if he may never stand up. His mouth, however, seems always in motion, as if chewing food for constant fuel.

He’s also a necessary soul mate to the carousing, drug-using Prince Hal (the excellent Toheeb Jimoh, an Emmy nominee for “Ted Lasso”), whose coming-of-age story — becoming, as he puts it, “more myself” — connects these two “Henry IV” plays. But the roustabout Hal’s dawning maturity costs him the companion he once held dear.