The term "inauguration" may feel slightly misleading.

After all, this is not his first time. Today's ceremony will be the fifth occasion Vladimir Putin has been sworn in as Russia's president, and it marks the start of another six years at the top.

He is already the Kremlin's longest-serving leader since Joseph Stalin, having been in power for nearly two and a half decades - 20 years as president, four as prime minister. By the end of this term, only Catherine the Great will be ahead of him - she ruled Russia way back in the 18th century.

So, to some, President Putin may feel more like Permanent Putin. There is a whole generation here that hasn't lived under anyone else.

The ceremony itself will be a lavish affair, inside the glittering Grand Kremlin Palace, Russia's "new" leader will swear an oath of loyalty to the people in front of thousands of guests. Former Hollywood action hero (and now Russian citizen) Steven Seagal and Germany's ex-chancellor Gerhard Schroder were among the celebrities and VIPs last time around in 2018.

A lot has changed since then, though. It will be fascinating to see who accepts their invitation.

Putin 5.0 is no surprise, of course. His victory in March's election was a given.

Read more from Sky News:Russia warns over use of British weapons in UkraineNative Americans hit out at 'offensive' land plansBody of British man found in Prague river The only question was his level of support. Officially, he won 87% of the vote, which was widely condemned by Western governments as being neither free nor fair.

The latest polling, however, points to a similar figure. According to the independent Levada Centre, Putin's current approval ratings are 85%, not far off his all-time-high.

In part, that is down to a "rally behind the flag effect.