There are some situations only siblings will understand, and this couldn't have been demonstrated better than by Sir Gary Oldman in a recent interview. In a new video, the Slow Horses star discusses his famous sister and makes a hilarious joke - however many may be surprised to learn who his sister is.

While Sir Gary is a recognisable star of the big and small screen, his older sibling is also a household name in Britain. Laila Morse (real name Maureen Bass, formerly Maureen Oldman) is the face of one of Eastenders' longest-standing and most iconic characters - Big Mo. Laila (80), who has played Mo Harris in the soap for more than two decades, is the big sister of Gary (68).

los angeles, california february 23: gary oldman arrives at the 31st annual screen actors guild awards at shrine auditorium and expo hall on february 23, 2025 in los angeles, california. (photo by maya dehlin spach/ga/the hollywood reporter via getty images)
Maya Dehlin/GA
Sir Gary Oldman at the Screen Actors Guild Awards in 2025.
london, england september 04: laila morse attends the tv choice awards at the dorchester on september 4, 2017 in london, england. (photo by david m. benett/dave benett/getty images)
Dave Benett
Laila Morse (Maureen Bass) is known for her iconic role as Big Mo in Eastenders.

Speaking to Radio Times in a new video, Sir Gary was asked about the Reebok advert Laila had starred in, which had gone viral. In a relatable sibling moment, Sir Gary looks confused. 'She's done a Reebok campaign?' he asks. 'What, like the shoes, Reebok?' He adds that he's 'not a social media person' so the attention around it had passed him by.

Shown the video for the first time, Gary laughs saying, 'Oh my god, that's hilarious,' and adds, 'You know, I'd recognise that laugh...anywhere.' He goes onto joke that his 'sister has a laugh that sounds, it's sort of like trying to start a truck or a car.' He then does a full impression, turning an invisible key as he says 'ah, ah, ah' to mimic his sister's laugh. The clips ends with him saying, 'good for her,' and waving at the camera to add, 'Well done Maureen!'

The whole interaction will likely be very familiar to anyone with brothers or sisters. Not only finding out something completely surprising about your sibling which they'd never mentioned, but also taking any opportunity to poke a little good natured fun at them. Plus, always ending with some genuine support.

Gary Oldman returns as Jackson Lamb in series 6 of Slow Horses, which returns to Apple TV on 16 September.