"The FIA has accepted him for sure," Ecclestone told the F1 business journalist Christian Sylt.
"They (the FIA) are going to put that (confirmation) out tomorrow," the 83-year-old said on Thursday.
The news is timely for the 61-year-old Haas Automation founder, having warned early this week that time was running out to organise a team for 2015.
"If we lose another month," Haas had warned, "I don't think we could do it."
Interestingly, Ecclestone said another two team applicants are currently being considered for inclusion on the 2015 entry list.
It was known that former HRT boss Colin Kolles is one, but it was believed that Serbian Zoran Stefanovich had withdrawn his bid after failing to reach an agreement with an engine supplier.
"We are looking at the other two," Ecclestone said, "but Haas has been accepted. "We are going to accept that Haas team."