Following the anti-hero Randall (Nicholson) who pleads insanity to get out of working in jail. Jack's character continuously through the film fights against the 'establishment' e.g. Nurse Ratched played by Louise Fletcher.

Jack thereby furthered his own counterculture image by association. 

He is widely regarded as one of the most successful and recognizable actors, composing a CV not only of his 'cool', 'rebel' roles but also of notable cult and pop culture characters. 

In his later roles, he is often seen to be playing the bad guy, often charming, however, or characters that have rude, bold, anti-hero qualities built into a leading man role. 

It is even hinted to the audience that perhaps he has gone a little mad.

It shows that even in his roles that are 'the good guys', he still retains that Nicholson specialty of the 'outsider'. 

A few most prevalent parts of his image are his charm, 'sex symbol' status, and adaptability to play loveable villains. 

In the 'Witches of Eastwick', he is paired with three younger counterparts, arguably all sex symbols of their own; Cher, Michelle Pfeiffer, and Susan Sarandon. This pairing with younger women happens a lot in Nicholson's films, noting that even in his aging he is still seen to be one of the most charming men in Hollywood. 

Moreover, his character in the film shows he is able to play charming, funny villains, not just serious cult favorites.

Notably, they ranged within the comedy genre, however, Jack's performances were still highlighted by his common Nicholson charisma and image. 

He is such a successful and beloved actor, he is not defined by his bad roles. Instead, audiences remember him as the crazed killer in 'The Shining', or one of the best Jokers, or the loveable drunk rebel from 'Easy Rider'. He is an actor that is so iconic, that you can't help but see his film roles when you look at him, therefore, his bad roles just sort of blend into the background.

The fact that these sorts of appearances can be found in a disproportionate number to other public appearances, such as him out for a walk or dinner with friends, shows his star image of being a 'golden' celebrity of sorts.

With the Oscars having a premeditated level of importance and exclusivity, the fact Jack can almost only be found here outside of film shows his level of notability within Hollywood. 

Arguably, to be famous with national and global audiences is one thing outside the 'glamourous' sphere of Hollywood, but to be famous with celebrities within that sphere is another. 

It speaks to his 'golden' status as a star, the fact that even celebrities get starstruck when around him speaks to his level of unattainability. 

Reddit user GoodShitBrain notes Jack's work in 'About Schmidt' (2002), writing "About Schmidt is so good. Later in his career, Nicholson plays a more subdued character. I really believed him to be a quiet, retired introspective Midwesterner". 

Film review website Rogerebert notes "Warren Schmidt is a man without resources. He has no intellectual curiosity." and also puts rather nicely that "Jack Nicholson is not such a man, and is famous for the zest he brings to living", (2002). 

While this shows Nicholson's range as an actor, it also compromises his star image, in that this is one of his only roles we don't see the normal Nicholson charm. 

However, it is important to note that this role does not change his star image as a whole, and Nicholson is still widely known as a rebel against a social structure. 

This interview presents Nicholson as an authentic celebrity, the interview Jack is placed in a domesticated space, giving a glimmer of his private sphere, for a professional interview. 
The fact he cries can be seen as authentic, it shows that the hardcore, distinguished actor is still normal and that emotions can be too much at times; even during a professional interview. It shows the person beyond the on-screen persona.
Moreover, it shows sincerity, the fact he is talking about his friend in such an emotional way, going back to Dyer's note that the star "means what he says", Jack crying, tells the audience that this is a moment of raw truth.