During the 1990s, the duo went on to become pop stars before going on to host numerous TV shows like SMTV, I'm A Celebrity.... and Saturday Night Takeaway.
Other names on the list include Love Island's Caroline Flack (6/1), Cannonball's Maya Jama (8/1), Ant and Dec's former co-star Cat Deeley at 10/1 and Diversity dancer Ashley Banjo at 20/1.
The Sun says that Donnelly and Astall, who married in 2015, have shared their happy news with Donnelly's Saturday Night Takeaway co-presenter Ant McPartlin, who last week stepped aside from the show to receive rehab treatment following his arrest for drink-driving.
A show insider claimed to the Daily Star on Sunday: "There's a very real possibility that Ant won't be available to present the next series of the jungle".
Ant I'm sure is as excited as you both are this could be a focus for him to get well & get back with you his best friend.
Declan Donnelly has just confirmed he is expecting his first child with wife, Ali in a heartwarming Twitter post.
Dec said: "Whilst I never thought I'd be in this position, after much discussion and careful consideration we've decided that the remaining two shows of this series of Saturday Night Takeaway will go ahead".
'We made a promise to take hundreds of deserving winners to Florida to watch the series finale, and we will honour that'.
Ant's latest set-back leaves their ITV documentary in the balance with the broadcaster hesitant to air the show due to its alcohol-fuelled scenes. "Everyone at ITV and the Takeaway team feels we owe it to the audience to complete the series".
Space station the size of a bus to fall from the sky
It is assumed that China is unable to control or communicate with the station, though Chinese officials have not confirmed that. There is uncertainty with any spacecraft reentry and most of that comes down to the density of the upper atmosphere.
Trump Trade War - South Korea and U.S. reach deal on quota
South Korea has negotiated an exemption from the United States' Section 232 steel tariff and instead will be subject to a quota. The Korea Iron & Steel Association welcomed the deal while saying the quota was smaller than the industry wanted.