The “Luther” star looked completely smitten as they sat in the front row at the Burberry show.
Idris, 45, wore a checked coat and Sabrina dazzled in red as they took their places on the coveted front row.
The couple held hands and kissed as they waited for the models to hit the catwalk.
Idris, 42, and Sabrina, 29, only had eyes for each other as they snuggled up in the audience.
Snaps taken at the venue show them sitting next to Matt Smith and his girlfriend Lily James.
Idris appeared to introduce the actors to his fiancee, who was seen shaking hands with both Lily and Matt.
The outing comes just days after Idris popped the question during a screening of his new film “Yardie.”
Staff at the Rio Cinema in Dalston confirmed the happy news on Twitter on February 10, revealing the actor got down on one knee to propose in front of the whole audience.
Posting a photo of Idris, the post revealed: “Another @riocinema first!”
“Still 5 days to Valentines Day but @idriselba went down on one knee and proposed to his girlfriend live on stage this morning before a preview of his film #Yardie.”
It added: “She said yes and there was much clapping and cheering.”
Idris, 42, and Sabrina, 29, have been together since last year when they met whilst Idris was filming “The Mountain Between Us” in Canada.
Idris has been married twice before, to Hanne ‘Kim’ Norgaard from 1999 until 2003 and to Sonya Nicole Hanklin in 2006.
He’s a father to 15-year old daughter Isan with ex Kim and he has a three year old son Winston with his ex girlfriend Naiyana Garth.