Pattinson, 23, was proudly cheering from the audience when his American girlfriend, 19, was named as the winner of the Bafta Rising Star accolade at the star-studded ceremony at the Royal Opera House.
After refusing to comment on their relationship for months, Pattinson finally broke his silence and admitted they were an item.
He told The Sun: 'It is extremely difficult but we are together, yes.
'We can't arrive at the same time because of the fans. It goes crazy. This was supposed to be a public appearance as a couple but it's impossible. We are here together and it's a public event but it's not easy.
'We have to do all this stuff to avoid attention.'
After the Baftas, the couple headed to the Grosvenor House Hotel for the after-party, where they were spotted leaving at a relatively-respectable midnight.
While Stewart attended the Elle Style Awards alone last night, Pattinson was busy working all day on his new film Bel Ami.
Romance rumours have surrounded the couple since the first Twilight movie came out in late 2008.
Their sizzling chemistry convinced 'Twi-hard' fans they were an item and was often commented on by their co-stars.
Catherine Hardwicke, who directed the first film, said: 'In terms of what Kristen told me directly, it didn't happen on the first movie. Nothing crossed the line while on the first film.
'I think it took a long time for Kristen to realise, "OK, I've got to give this a go and really try to be with this person."'
Hardwicke admitted she noticed the chemistry between the pair during filming, but warned Pattinson off Stewart, because she was 17 at the time, which would make her underage in several U.S. states.
She said: 'After I cast him, I told Rob, "Don't even think about having a romance with her. She's under 18. You will be arrested."'
The couple repeatedly denied rumours of a romance and, until last Spring, Stewart was dating long-term boyfriend Michael Angarano.
Stewart and Pattinson were rumoured to have finally gotten together when they filmed the first Twilight sequel New Moon last summer."