Former X Factor judges Sharon Osbourne and Louis Walsh have been reunited on TV as they became the first stars to enter the Celebrity Big Brother house.

The revived reality series kicked off with a “secret mission” for Osbourne and Walsh, who appeared on The X Factor alongside Simon Cowell for many years.

The pair were given a “secret lair” where they will judge which three celebrity housemates to put in the “danger zone” before choosing one housemate to automatically face the public vote this week.

As the first “celebrity lodger” to enter the house, Osbourne described herself as the “original reality star”.

“I am good fun to live with, so my husband says. Chaos, I don’t cause it, it just seems to go on around me even though I do have a big spoon to mix it,” she said in a pre-recorded video.

“I definitely say what is on my mind, I think at my age I have earned it. I am so excited to be involved with Celebrity Big Brother because it is going to be a bumpy ride.”

Walsh greeted Osbourne, saying “what are we doing?”, before telling Big Brother he was “absolutely delighted” to be reunited with Osbourne, adding “we’ve got loads to catch up on”.

The voice of Big Brother told the pair: “I’ve brought the two of you back together because I know you are used to judging people on first impressions. Sharon, you have a decision to make, and Louis you are here to help Sharon make that decision.”

Walsh said in a pre-recorded video: “I say things I shouldn’t say, my mouth has got me into trouble. I’m not easy to live with, I get up late, I go to bed late.

“Celebrities have massive egos, I hope I get on with them because I have an ego too. I’ve never done anything like this in my life… I’m here just to have fun.”

Osbourne and Walsh sat in their secret lair as celebrities began entering the house, with Osbourne commenting on Strictly Come Dancing professional Nikita Kuzmin’s good looks, while Walsh said Love Island winner Ekin-Su Culculoglu had been on “every show”.