Hollywood star Kirstie Alley asked “what have I let myself in for?” as she became the first person to enter the Celebrity Big Brother house.

The 67-year-old actress, known for roles in TV series Cheers and the Look Who’s Talking films, was unveiled by host Emma Willis as the Channel 5 series kicked off.

In her introductory vidoe, Alley talked about her acting career, as well as her highly-publicised battle with her weight.

She told Willis she was “so excited” before entering the house, and added: “I stay in my pyjamas all day… sometimes by nightfall I doll up and put on some heels.”

Entering the house and climbing down the staircase, Alley joked: “What have I signed myself up for?”

Immediately after making her way into the famous TV lock-up, Big Brother summoned her to the diary room, where she was given a secret task.

Alley was told she has been made the President of the CBB house, to which she quipped: “Do you get assassinated for that?”

She was told that she would have special powers and privileges, but that she must not let her fellow housemates know her secret role until they are all inside the house.

She will have to ask her co-stars questions about themselves in order to help the public to vote for one of them to become her vice president.

Former Coronation Street star Ryan Thomas was the second star to enter the house, and when he saw Alley, he shouted: “Look who’s talking now!”

At the start of the show, Willis took viewers around the new-look CBB house, which took 12 weeks to create and includes a concealed staircase for the first time in several years.

Willis said the house has “more cameras than ever before”, and unveiled the bathroom, which has walls with holes in.

She said the house was “designed to feel like a retreat for the celebrities”, away from the “media storms” they have each been involved in.