Jennifer Aniston and Justin Theroux look estatic as they honour pal Ben Stiller

Newly engaged Jen and Justin couldn't have looked happier on the red carpet at the American Cinematheque Awards

Jennifer Aniston and Justin Theroux beamed as they posed for photographs at the American Cinematheque Awards in Los Angeles. Loved up much?

The newly engaged duo arrived at the glamorous event in matching monochrome ensembles with Jen, 43, looking radiant and chic in a strapless, floor-length, gown by Valentino and Justin, 41, dapper in a classic tuxedo.

Aniston and Theroux laughed and chatted as they posed happily for photos on the red carpet before they went inside to honour their actor pal Ben Stiller, who was being bestowed with the gala's big award given annually to 'an extraordinary artist currently making a significant contribution to the art of the Moving Picture.'

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Having showed off her whopping diamond engagement ring to her fellow guests sat at her table, Jen took to the stage to introduce a video package of Ben Stiller's onscreen romances. 'His package is surprisingly large,' she joked. 'Very expansive, and its lasting power speaks for itself.'

What do you think of Jennifer Aniston's red carpet look? Do her and Justin Theroux make the perfect couple? Let us know in the comment box below.

Watch: Jen and Justin hit the red carpet at last night's event in the video below:

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