diff --git a/Project.toml b/Project.toml
index 5ec4a34c..20764dd5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,18 +1,21 @@
 name = "FillArrays"
 uuid = "1a297f60-69ca-5386-bcde-b61e274b549b"
-version = "1.7.0"
+version = "1.8.0"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+PDMats = "90014a1f-27ba-587c-ab20-58faa44d9150"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [weakdeps]
+PDMats = "90014a1f-27ba-587c-ab20-58faa44d9150"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [extensions]
+FillArraysPDMatsExt = "PDMats"
 FillArraysSparseArraysExt = "SparseArrays"
 FillArraysStatisticsExt = "Statistics"
 
@@ -20,6 +23,7 @@ FillArraysStatisticsExt = "Statistics"
 Aqua = "0.8"
 Base64 = "1.6"
 LinearAlgebra = "1.6"
+PDMats = "0.11.17"
 Random = "1.6"
 ReverseDiff = "1"
 SparseArrays = "1.6"
@@ -31,6 +35,7 @@ julia = "1.6"
 [extras]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+PDMats = "90014a1f-27ba-587c-ab20-58faa44d9150"
 ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
@@ -38,4 +43,4 @@ Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Aqua", "Test", "Base64", "ReverseDiff", "SparseArrays", "StaticArrays", "Statistics"]
+test = ["Aqua", "Test", "Base64", "PDMats", "ReverseDiff", "SparseArrays", "StaticArrays", "Statistics"]
diff --git a/ext/FillArraysPDMatsExt.jl b/ext/FillArraysPDMatsExt.jl
new file mode 100644
index 00000000..d5a0892d
--- /dev/null
+++ b/ext/FillArraysPDMatsExt.jl
@@ -0,0 +1,12 @@
+module FillArraysPDMatsExt
+
+import FillArrays
+import FillArrays.LinearAlgebra
+import PDMats
+
+function PDMats.AbstractPDMat(a::LinearAlgebra.Diagonal{T,<:FillArrays.AbstractFill{T,1}}) where {T<:Real}
+    dim = size(a, 1)
+    return PDMats.ScalMat(dim, FillArrays.getindex_value(a.diag))
+end
+
+end # module
diff --git a/src/FillArrays.jl b/src/FillArrays.jl
index 7ca7b78e..d6d21f67 100644
--- a/src/FillArrays.jl
+++ b/src/FillArrays.jl
@@ -669,7 +669,8 @@ include("fillalgebra.jl")
 include("fillbroadcast.jl")
 include("trues.jl")
 
-@static if !isdefined(Base, :get_extension)
+if !isdefined(Base, :get_extension)
+    include("../ext/FillArraysPDMatsExt.jl")
     include("../ext/FillArraysSparseArraysExt.jl")
     include("../ext/FillArraysStatisticsExt.jl")
 end
diff --git a/test/runtests.jl b/test/runtests.jl
index aee883da..ef9f463c 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,4 +1,4 @@
-using FillArrays, LinearAlgebra, SparseArrays, StaticArrays, ReverseDiff, Random, Base64, Test, Statistics
+using FillArrays, LinearAlgebra, PDMats, SparseArrays, StaticArrays, ReverseDiff, Random, Base64, Test, Statistics
 import FillArrays: AbstractFill, RectDiagonal, SquareEye
 
 using Aqua
@@ -2193,3 +2193,13 @@ end
     @test ReverseDiff.gradient(x -> sum(abs2.((Zeros{eltype(x)}(5) .+ zeros(5)) ./ x)), rand(5)) == zeros(5)
     @test ReverseDiff.gradient(x -> sum(abs2.((zeros(5) .+ Zeros{eltype(x)}(5)) ./ x)), rand(5)) == zeros(5)
 end
+
+@testset "FillArraysPDMatsExt" begin
+    for diag in (Ones(5), Fill(4.1, 8))
+        a = @inferred(AbstractPDMat(Diagonal(diag)))
+        @test a isa ScalMat
+        @test a.dim == length(diag)
+        @test a.value == first(diag)
+    end
+end
+