The 22-year-old quit The X Factor after deciding that he could not commit to life in a boyband.
In a statement, Baptiste - pictured far right in the photo below - praised his former bandmates Charlie Healy, Andrew Merry and Derry Mensah and said that he is confident The Risk can win The X Factor without him.
"It's been a really tough decision but I have decided to leave The Risk," he declared. "I don't believe my future lies in a boyband and it's not fair on Charlie, Derry and Andy to remain in the band when I am not truly committed to it for the long term.
"I believe The Risk can win The X Factor and I'm backing them all the way. I count them as my friends so I know we'll stay in touch."
The Risk added: "We're gutted to be losing Ashley but we back him all the way in his decision. We're going to miss him, but The Risk are going to carry on in the competition and hope we can do our mate and all our supporters proud."
An X Factor spokesperson said: "We're disappointed to be losing Ashley from the competition but we fully support his decision and wish him well for the future."
Following Baptiste's departure, The Risk asked their mentor Tulisa Contostavlos if they could continue as a four-piece with former Nu Vibe member Campbell - pictured far right in the photo below - in the lineup.
"We're devastated that Ashley has decided to leave but we respect his decision," the group said. "After taking in the news we decided that we didn't want to be a trio, we really wanted another member.
"We have always liked Ashford, right from Boot Camp, and always had a strong bond with him. He's mega talented and will bring so many qualities to the group. We're so glad he said yes and we can't wait to get rehearsing."
Contostavlos gave her backing to the decision and said that Campbell would be a "fantastic fit" for The Risk.
"I'm gutted to see Ashley go, we'll all really miss him but we respect his choice and wish him all the best for the future," she said.
"The Risk boys really wanted Ashford to replace Ashley and I think he's got a great voice, he's a fantastic fit and I totally support their decision."
Campbell additionally claimed that the other members of Nu Vibe, who were eliminated in the second week of The X Factor live shows, have given their blessing to his move.
"I couldn't believe what I was hearing when I got the call," the 16-year-old said. "I had to speak to the Nu Vibe boys first and once they gave me their blessing I was straight back on the phone to grab the offer. It's unbelievable and now I've got to work even harder after my break."
The new-look version of The Risk have just 24 hours to prepare for their first performance together on The X Factor's next live show.
The X Factor returns tonight at 8pm on ITV1.
> X Factor's The Risk: 'We can take over Westlife's stools'
Watch Digital Spy's recent interview with The Risk below: