Ben Affleck couldn't hide his pride in his girlfriend at the Emmy Awards on Sunday (17.09.17).

Ben Affleck

Ben Affleck

The 'Argo' filmmaker and producer Lindsay Shookus opted out of making their red carpet debut as a couple at the glitzy ceremony, which honoured excellence in television, but they showed no signs of trying to conceal their relationship and the 45-year-old actor was elated when his partner's show, 'Saturday Night Live', won the Outstanding Variety Sketch Series accolade.

An onlooker told Us Weekly magazine: "He jumped up and cheered when 'SNL' won.

"He's sitting with all of 'SNL' in the centre of the theatre. He's clearly her plus-one."

And following the win at Los Angeles' Microsoft Theatre, Lindsay and Ben were seen "holding hands and whispering and smiling."

The couple went public with their relationship in July after meeting in London, and enjoyed a string of dates, including going to see Sam Mendes' play 'Ferryman' in the English capital.

A source said at the time: "They are in the early stages [of their relationship]. It's more than a summer fling. They are having fun and care for each other. It's early and they are taking it slow."

And the 'Live by Night' actor's estranged wife Jennifer Garner - who filed for divorce in April, almost two years after they split - is said to be fine about their relationship.

The 'Alias' actress - who has three children Violet, 11, Seraphina, eight, and Samuel, five, with Ben - knew about the romance before she decided to accompany Ben on holiday with their brood in July.

An insider revealed at the time: "Jen knew about the new relationship and still chose to go on vacation with Ben for the 4th of July. She is OK with it."