Michael Bay admitted the global premiere of 'Transformers: The Last Knight' was a ''bittersweet'' experience for him.

The 52-year-old filmmaker has helmed all five of the 'Transformers' movies since they started back in 2007 but recently revealed he will no longer be involved in the franchise after the fifth movie and as he attended the glitzy event in London's Leicester Square on Sunday (18.07.17), Bay spilled that he felt a bit ''sad'' to know it was his final time walking the red carpet as the series' director.

Speaking at the premiere - which was attended by lead star Mark Wahlberg - he said: ''It's sad. It's my last one. Seeing all the characters and actors, it is a little bittersweet.''

Although Bay is no longer attached to the franchise, when asked if he could be persuaded to return he said he needs a ''little time'' after only finishing the latest instalment ''five days ago''.

Co-producer Lorenzo di Bonaventura, who also attended the premiere, will try and get Bay back on board for another Autobot adventure.

He said: ''He's left it in a great place and he wants to leave it that way. He has broken the mould with this one and allowed the franchise to possibly carry on in the future.

''I will press on Michael to do one more. We are all going to give it a shot.''

Although Bay is finished with the franchise for now, Paramount and Hasbro, who own the rights to the brand, are moving ahead with the next movie and are confident they can find the right director to helm the project and stick to their planned release schedule.